Browsing by Author "Weerasooriya, M.K.B."

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Alkaline lipase from rice bran; Purification. Characterization of and evaluation its potential to use as a bio-detergent
(Culture, Globalization and the Developing World, 2nd ICSS, 2013) Weerasooriya, M.K.B.; Singharam, I.
Removal of fatty nature stain is a major problem in laundry cleaning. Currently fat containing dirts are removed by saponification at high temperature under high alkaline conditions. The method costs energy as well as lower the texture and quality of textile fabrics. Therefore, there is a need of low temperature active alkaline lipases to save the energy and to maintain the quality of fabrics. Novozyme Company in Denmark, and Genecor International, in India currently produce microbial lipases to use in the detergent industry. Though these commercial lipases stable in alkaline pH, 2-3 wash cycles are needed to obtain a significant removal of lipid stain .Cost production of these enzymes are also high. Hence, their industrial use has been limited. Objective of the paper is to study Purification. Characterization of rice bran lipase and evaluation it?s potential to use as a bio-detergent. Lipase was extracted from rice bran partially purified by DEAE Cellulose chromatography. Its pH stability under alkaline conditions, a temperature kinetics and lipolytic activity towards different lipids were studied. Washing performance tests also carried out to test its potential to remove fatty nature stains. Enzyme showed optimum reactivity at 30-40�C optimum stability around pH 8-10. High lipolytic activity toward all the tested lipids eg. Olive, soybean, sun flower, coconut oil, margarine and butter. Washing performance tests also showed stain caused by coconut oil (1.00ml) can be completely removed by treating the fabric with lipase 1mg/ml at 30�C for 15min. Findings showed that rice bran lipase can be used as a potential candidate in bio-detergent industry.
Amylase production by A, niger under solid state fermentation using passion fruit peel as the carbon source
(Sri Lanka Association for the Advancement of Science, 2016) Lakmini, S.K.; Weerasooriya, M.K.B.
Arginine Decarboxylase from the pathogenic fungi, Colleotrichum gleosporosides : Purification and Properties
(Journal of Science of the University of Kelaniya Sri Lanka, 2003) Weerasooriya, M.K.B.; Handagiripathira, H.M.N.L.; Wijewickrama, G.T.
Arginine decarboxylase, a polyamine biosynthetic enzyme, was isolated from a phytopathogenic fungi, Colletotrichum gleosporoides, which causes Anthracnose in wide range of plants in many parts ofthe world. The enzyme was purified 25 fold with 16.7% recovery by elution through Sepharose 4B gel column and DEAE Cellulose ion exchange column. As determined by Sepharose 4B gel chromatography, the native molecular mass of the purified enzyme was ~265kDa. SDS-PAGE of the purified enzyme showed two bands around 65 kDa and ~25 kDa, suggesting that possibly this enzyme could be a hexamer of above two sub units. Optimum pH and temperature for the enzyme was 5.2 and 40�C respectively . Beyond 50�C enzyme activity slowly declined and was almost deactivated by 80�C. Approximate Km of the enzyme for the substrate arginine was 67mM.
Cell free enzyme studies on Napthal Reductase from Verticillium, Dahliae
(1993) Weerasooriya, M.K.B.
Effect of usage of mobile phone in trouser pocket on quality of semen parameters
(Faculty of Graduate Studies, University of Kelaniya, 2015) Munasinghe, D.A.L.; Weerasooriya, M.K.B.; Liyanage, J.A.; Wakkumbura, H.P.
A cross sectional study was carried out in the fertility clinic of Gampaha Wickramarachchi Ayurveda hospital during the period of August 2014 to August 2015 to find out the effect of carrying mobile phone in trouser pocket on the quality of semen parameters. Mobile phone has become an essential instrument among the lives of modern society. It assists to globalize the world. The disadvantage is the emitting of harmful rays when it‘s in use or switch on mode. However this bad effect basically depends on the way of handling the item. In vitro studies in foreign countries have shown that mobile rays have a negative effect on sperm motility. However, local studies on subject are handful in amount. Thus the current study was set up to trace the effect of switch on mobile phones kept in trousers on semen parameters. Every male who visited the clinic for fertility issue was personally evaluated on consent to gather the behavioral data. The semen of each was also collected (after 3 days absent from ejaculation) and analyzed separately. Out of 81 subjects 51 were used to carry the phone in trouser pocket as a custody. However when comparing the average semen parameters of them such as volume, sperm count, sperm motility and morphology with the same of non-users, it was clear that though there was a slight reduction of mentioned parameters in the test group it was statically not significant (P>0.05). Thus according to the final result the usage of mobile phone in trouser has a less effect on the quality of semen parameters. However this could be due to non-continuous usage of switch on mobile phone in the particular site. More over its better to keep the phone out of the site of testis when concerning male fertility.
The Effects of Thermal Treatment on Antioxidant Properties of Fruit Peels from Pomegranate (Punica granatum L.) Cultivars Grown in Sri Lanka
(Faculty of Graduate Studies - University of Kelaniya, Sri Lanka, 2021) Panapitiya, P.D.S.N.H.; Weerasooriya, M.K.B.
Pomegranate peel (PP), a primary by-product of the pomegranate juice producing industry, is reported to possess diverse range of bioactive compounds which are believed to bear anticancer, antimicrobial, anti-inflammatory and antioxidant properties. In recent years, natural antioxidants are gaining more and more attention due to its possible medicinal and food applications and have preferred by consumers over synthesized antioxidants. Heat treatment is known as processing step for fruit peels to release variety of bound polyphenolics from tissues of peels by improving their bioavailability or modifying chemical structure to enhance absorption, and to intensify nutritional effects. Thus, the aim of this study was to determine the effects of heat treatment on antioxidant properties of pomegranate peel (PP) of Sri Lankan cultivars, named as Nayana, Kalpitiya red, and Nimali. Peel powder (2.00 g) heated at 160 °C in an oven for 2 hours and non-heated peel powder of each cultivar extracted with ethanol (70% v/v, 25.00 mL). Free radical scavenging activities of PP extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and expressed as IC50 value. Color changes of PP powder before and after thermal treatments were investigated. All the extracts exhibited significant dose dependent inhibition activity. Therefore, DPPH scavenging activity increased as the concentration of the sample was increased up to a certain concentration that was varied from cultivar to cultivar. According to the results, heat-treated PP powders of each cultivar showed significantly higher (p<0.05) antioxidant activity compared to the non-treated PP powder of each cultivar. Antioxidant activities of PP increased due to the thermal treatment. IC50 values of the non-treated PPs of Nimali, Kalpitiya red and Nayana cultivars, were found to be 19.067 ± 0.291c, 21.067 ± 0.233b and 22.233 ± 0.145a μg/mL, respectively, while the IC50 values of heat-treated PP samples of cultivars were 11.100 ± 0.265c, 17.600 ± 0.115b and 20.400 ± 0.115a μg/mL. All the IC50 values of PP extracts were compared with that of Gallic acid (GA) as the standard compound and IC50 value of GA was 4.65 μg/mL. Hence, antioxidant activities of both heat-treated and non-treated PP extracts were lower than that of GA. The peel of Nimali exhibited the highest DPPH radical scavenging properties than the other cultivars, in which antioxidant properties were highly improved by heat treatment and also, its change in IC50 value (ΔIC50) before and after heat treatment, is significantly higher than other cultivars. It might be higher concentrations of polyphenolics released. Initial color of PP powder of each cultivar was converted from brownish yellow to dark brown during heat treatment. IC50 values were significantly different (p<0.05) among cultivars and temperature. According to the results, thermal treatment had no negative effects on the antioxidant capacities of the PP powder up to 160 °C. Therefore, bakery products (specifically cookies) can be considered as the most acceptable carriers of such pomegranate peel powder supplements. Furthermore, examined heat treatment can be used as an acceptable method to sterilize the PP powder. Considering the findings, thermal treatment might be a good alternative strategy for improving health benefits of PP, adding value to the PP, and could be helpful for development of potential dietary supplements. PP powder which possesses extremely high antioxidant properties, has a great potential to be used as a source of food additives in food products such as natural food preservatives (antioxidants) and a therapeutic agent.
Evaluation and comparison of antioxidant properties and total phenolic content of pomegranate (Punica granatum L.) peel and juice
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Panapitiya, P. D. S. N. H.; Weerasooriya, M.K.B.
Pomegranate peel is currently a waste but contains valuable, rich with a diverse range of bioactive compounds. The objective of the present study was to assess the antioxidant properties by IC50 value and FRAP value, total phenolic content (TPC), total flavonoid content (TFC) and total anthocyanin content (TAC) of the peel (PP) and the juice (PJ) of local pomegranate cultivars, Nayana, Nimali and Kalpitya red. Antioxidant properties were tested by FRAP and DPPH assay. TPC was measured spectrophotometrically using the Folin Ciocalteu method and expressed as mg Gallic acid equivalents (GAE)/gram. TFC was evaluated by the aluminum chloride assay. TAC was detected by the vanillin assay. The TAC and TFC of PP of Nimali, Nayana and Kalpitya red cultivars were 22.12 ± 0.20, 49.05 ± 0.30 and 69.08 ± 0.57 mg catechin equivalents (CE)/g and 67.67 ± 0.59, 59.58 ± 0.85 and 75.99 ± 0.85 mg rutin equivalent (RE)/g respectively. The TAC of PJ ranged from 0.40 ± 0.01 to 2.82 ± 0.03 mg CE/g was nearly 60 times less than that of PP of the same cultivar. The TFC of PJ ranged from 0.39 ± 0.00 to 0.80 ± 0.00 mg RE/g was nearly 100 times less than that of PP. The TPC and FRAP values of PP of Nimali, Nayana and Kalpitya red cultivars were 469.67 ± 8.97, 413.92 ± 4.75 and 318.82 ± 4.66 mg GAE/g and 6690.00 ± 153.00, 4270.60 ± 83.00 and 4512.00 ± 14.00 μmol Fe2+/g respectively. The TPC of PJ varied from 0.87 ± 0.02 to 1.98 ± 0.04 mg GAE/g was nearly 300 times less than that of PP. The FRAP values of PJ ranged from 15.57 ± 0.36 to 40.18 ± 0.29 μmol Fe2+/g were nearly 200 times less than that of PP. The IC50 values of PP of Nimali, Nayana and Kalpitya red cultivars were found to be 14.20, 20.40 and 18.00 μg/mL respectively. The IC50 values of PJ were in the range of 915-3098 μg/mL, nearly 100 times higher than that of PP. The results revealed that PP contains exceptionally high TPC and antioxidant properties observed by IC50 and FRAP values with respect to PJ of the same cultivar. The PP of Nimali cultivar had the highest antioxidant properties and TPC. The PP of Kalpitiya red cultivar possessed the highest TFC and TAC. Thus, PP has a high potential to be utilized as a resource of bioactive compounds. The results proved that there is no correlation between phenolic compounds and the antioxidant properties. All the parameters tested were significantly different (p<0.05) among the cultivars.
Evaluation of Nutritional Potential and Composition of Peel of Pomegranate (Punica granatum L.) Cultivars Grown in Sri Lanka
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Panapitiya, P.D.S.N.H.; Weerasooriya, M.K.B.
Pomegranate peel is a valuable waste rich with diverse range of bioactive compounds, which possesses antioxidant, cardio preventive, antimutagenic, antibacterial and antiviral activities. Apart from that, peel is believed to contain a significant level of nutritive ingredients such as minerals, organic acids, fat, protein, dietary fiber and vitamins. If the nutrient contents are significantly high that will open up a new avenue to develop a value added food product with high therapeutic and nutritional value. Nutritional composition of fruit peel can be varied depending on the cultivar, geographical and climatic factors. Hence, the study was aimed on the nutritional composition of the pomegranate peel (PP) of three Sri Lankan cultivars, named as Nayana, Kalpitiya red and Nimali. Fresh peels were dried in shade for 3 days, powdered and used for the analysis. Moisture content was measured by leaving the peel powder in hot air oven at 105 °C until get a constant weight. Crude proteins, crude fibers, lipids and total ash were analyzed according to the methods outlined in AOAC (2000) and carbohydrates content was determined according to FAO (1982) by difference method. Caloric value of each cultivar was calculated by the percentage sum of carbohydrates and proteins multiplied by a factor of 4 (kcal/g) and total lipids multiplied by a factor of 9 (kcal/g). All the experiments were performed in triplicate. The results showed that the crude protein, lipid, carbohydrate contents and caloric values were ranged from 3.35 ± 0.29 to 4.73 ± 0.20%, from 0.67 ± 0.01 to 1.01 ± 0.02%, form 68.66 ± 0.17 to 70.33 ± 0.92% and from 297.13 to 304.59 kcal/100 g dry weight, respectively. The moisture, total ash and crude fiber contents were varied from 6.02 ± 0.01 to 6.82 ± 0.02, from 3.74 ± 0.04 to 4.55 ± 0.06% and from 13.60 ± 0.61 to 16.44 ± 0.29% respectively. The highest ash and carbohydrate contents were in the peel of Kalpitiya red whereas the highest crude fiber and fat contents were recorded in the peel of Nimali. The peel of Nayana cultivar had the highest protein content (4.75%), followed by the peels of Kalpitiya red and Nimali cultivars. According to the results, peels of all three cultivars, are rich with crude protein, crude fiber and total ash and carbohydrate contents and serve as a good source of energy. High amounts of total ash in peels indicate high values for mineral composition. According to the statistical analysis, all the parameters except carbohydrate content were significantly different (p<0.05) among the cultivars. All these findings revealed that the PP exhibits higher nutritional potential and can be used as good ingredients in formulation of food products with numerous health benefits. Moreover, utilization of these low cost wastes may provide considerable economic benefits to food processors.
Hypoglycaemic and Hypolipidaemic effect of an ethylacetate fraction of Artocarpus heterophyllus (jak) leaves in streptozotocin induced diabetic rats
(Sri Lanka Association for the Advancement of Science, 2009) Chackrewarthy, S.; Jayasekera, S.; Thabrew, M.I.; Weerasooriya, M.K.B.
Previous investigations have shown that aqueous extracts of Artocarpus heterophyllus (jak) leaves (family Moraceae) can exert significant hypoglycaemic activity, and improve the glucose tolerance of healthy rats and humans, and newly diagnosed maturity onset diabetic patients. A preliminary study carried out by the authors with fractions separated from A. heterophyllus leaves showed that the ethylacetate fraction exerts the greatest hypoglycaemic activity in rats. The objective of the present study was to determine the effects of prolonged administration of ethylacetate fraction of A. heterophyllus leaves on serum glucose and lipid levels in streptozotocin induced diabetic rats since no reports are available on the effects of A. heterophyllus leaves on hyperlipidaemia associated with diabetes despite its clinical significance. Oral administration of the ethylacetate fraction (20 mg kg -1 bw) of A. heterophyllus leaves daily for five weeks significantly lowered serum glucose, cholesterol and triglyceride levels in streptozotocin induced diabetic rats. Compared to the control diabetic rats, the extract treated rats had 39% less serum glucose, 23% lower serum total cholesterol and 40% lower serum triglyceride levels and 11% higher body weight at the end of the fifth week. The percentage reductions in the serum parameters mediated by the test fraction were comparable with those produced by glibenclamide (57%, 32% and 42% reductions in serum glucose, cholesterol and triglycerides, respectively). The stimulation of insulin release by active principles in the ethylacetate fraction may be one of the mechanisms by which this fraction mediates its hypoglycaemic effect. It may be concluded that the ethylacetate fraction of A. heterophyllus leaves contain one or more hypoglycaemic and hypolipidaemic principles which have the potential to be developed further for the treatment of diabetes specifically associated with a hyperlipidaemic state.
Invertase of Woodfordia Fruticosa (Malitta): purification and its properties
(University of Kelaniya, 2000) Weerasooriya, M.K.B.; Yatawara, H.P.
Iron content and availability studies in some Sri Lankan rice varieties
(International Journal of Food Science and Technology, 2011) Herath, H.M.T.; Rajapakse, H.; Wimalasena, S.; Weerasooriya, M.K.B.
Thirty-eight rice varieties, grown in Low Country Wet Zone, during Yala (2006) and Maha (2006 . 2007) seasons were screened for stable high iron rice varieties and were statistically analysed. Iron contents ranged 1.89.3.73 mg 100 g)1 and varied significantly (P < 0.05) with variety and season. Selected fifteen high iron rice varieties, at degree of polishing 8.10% were analysed for iron, zinc and phytate. High iron contents in endosperm were observed in Suduru Samba (0.47 mg 100 g)1), Basmati 370 (0.37 mg 100 g)1), Kalu Heenati (0.42 mg 100 g)1), Rathu Heenati (0.44 mg 100 g)1) and Sudu Heenati (0.37 mg 100 g)1). Phytate contents of polished rice varieties ranged from 200.300 mg 100 g)1. Large reduction in iron content (84.5.93.6%) was observed in polished rice while the reduction in phytate content (18.9.40.8%) was low. Percentage dialyzability of iron in selected endosperm high iron rice varieties ranged from 1.73 to 8.71. Dialysability of iron in cooked polished rice did not show a relation to the phytate content in raw rice.
Isolation of alkaline lipase from rubber seed - Partial purification, characterization and its potential applications as a detergent additive
(Indian Journal of Chemical Technology, 2012) Weerasooriya, M.K.B.; Kumarasinghe, A.A.N.
Methyl Transferase, a Polyketide Biosynthetic Enzyme from Dreschlera Monoceras: Purification and Properties
(University of Kelaniya, 2007) Weerasooriya, M.K.B.; Crosby, J.
Methyl transferase, a polyketide biosynthetic enzyme in monocerin biosynthesis was isolated and purified from Dreschlera monoceras. The enzyme was purified to near homogeneity with 11.1% recovery, using ammonium sulphate fractionation followed by ultra filtration, SP Sepharose chromatography and gel filtration chromatography. The molecular mass of the purified enzyme as determined by elution through Superdex TM gel filtration chromatography was found to ~ 165kDa. SDS-PAGE of the purified enzyme showed a single band at ~55kDa indicating that possibly enzyme could be a trimer of 3 subunits. The enzyme showed optimum pH at 7.5-7.7, whereas optimum assay temperature was 35-37°C. Enzyme was stable up to 45°C and above this temperature enzyme activity slowly declined and inactivated around 70°C. Apparent Km of the enzyme was found to be ~ 0.083mM.
Novel poly amine biosynthetic inhibitors to control the phytopathogenic fungal diseases
(University of Kelaniya, 2008) Weerasooriya, M.K.B.; Thambugala, T.A.N.S.
Fungal polyamines play a major role in controlling the growth and development of the fungal cells. Higher polyamine levels enhance the fungal growth whereas lower levels retard the growth. Therefore depleting polyamine level by selective inhibition of poly amine biosynthesis through specific inhibitors, could be used to control variety of fungal diseases in plants. Following this line of thinking we aimed to identify potential and specific inhibitors of polamine biosynthetic enzymes. The fungus Colletotrichum gleosporoides which causes anthracnose in a wide range of plant in many parts of the world was selected for the study. Arginine decarboxyalse, a rate limiting enzyme of the polyamine biosynthesis was isolated from fungus. Fungus was grown in Cook's 2 media. Crude enzyme extract was prepared from 12-13 days old cultures, mycelia were harvested, immersed in citrate buffer (50mM, pH 5.6) and ground in a motor with a pestle at 4°C. Thus prepared crude enzyme extract was partially purified 25 fold with 16.7% recovery by ammonium sulphate fractionation (0-25% ) followed by DEAE cellulose and gel filtration chromatography. Enzyme activity was assayed by detecting the released carbon-dioxide with warbug manometer. Several plant extracts were tested as possible inhibitors for the enzyme. Of them Leaf extract of Ocimum sanctum (maduru thala) and Jatropha curcus (Rata Endaru) and tuber extract of Acarus calamus (Wadha kaha) and Zingiber zerumbet (Wal inguru) were found as inhibitors for the enzyme where as leaf extract of Ocimum basillicum (Suwanda thala) and tuber extract of Costus speciosus (Thebu) were found as non inhibitors for the enzyme. 1 00% inhibition of the enzyme was seen at 0.1 g/ 1 ml concentration level of Ocimum sanctum and Jatropha curcus and 0.08g/lml level of Acarus calamus, and Zingiber zerumbet.
Ornithine decarboxylase from Colletotrichum gloeosporioides: its purification, properties and inhibitors
(Sri Lanka Association for the Advancement of Science, 2011) Weerasooriya, M.K.B.; Thambugala, T.A.N.S.
Fungal polyamines play an indispensable role in controlling the growth and development of fungal cells. High levels of polyamines enhance cell growth where as low levels retard growth. Therefore, depleting polyamine levels by selective inhibition of polyamine biosynthesis by specific inhibitors will provide a key to controlling a variety of fungal diseases in plants. With this aim, Ornithine decarboxylase, a rate limiting enzyme of fungal polyamine biosynthesis, was isolated from the fungus Colletotrichum gloeosporioides, and purified by ammonium sulphate fractionation followed by DEAE cellulose and sepharose 4B gel filtration chromatography. The enzyme was purified 11.56 fold with 58 % recovery. The purity of the enzyme fraction was screened by SDS-PAGE. Two bands were seen at ~65kDa and ~ 25 kDa. The native molecular mass of the enzyme as determined by sepharose 4B gel filtration chromatography was ~ 130KDa. Kinetic studies of the enzyme reaction showed that enzyme exhibited higher activity in the range of 35-45°C with a maximum at 40°C. Effect of pH on enzyme activity showed that the enzyme possesses high activity in the range of 4.8- 5.4 with an optimum at pH 5.2. Inhibition studies with the enzyme showed that eugenol, linalool, α-pinene, geraniol , citral were not inhibitors. Cyclohexylamine, methyl isoleucine, methyl isothiourea and methyl hydrazine carboxylate act as inhibitors for the enzyme.
Potential utilization of Sri Lankan rice varieties to combat iron deficiency anaemia
(Research Symposium 2009 - Faculty of Graduate Studies, University of Kelaniya, 2009) Herath, H.M.T.; Rajapakse, D.; Wimalasena, S.; Weerasooriya, M.K.B.
Rice is the staple food among Sri Lankans. Potential to use rice as a vehicle, to combat population‟s iron deficiency anemia, has been emphasized in present study. Forty two rice varieties were grown in Complete Randomized Block Design (CRBD) at Bombuwala (iron rich soil > 500ppm) and Batalagoda (iron non-rich soil ~ 100 ppm) during Yala and Maha season of year 2006 and 2007. Duplicates were screened for stable high iron rice varieties. The results of pooled analysis including total variation of iron contents in two seasons in two locations showed that the iron contents ranged from 1.75 mg/100g to 3.23 mg/100g. A significant difference (p = 0.05) in iron contents was observed for the varietal, locational and seasonal. Fifteen high iron rice varieties were selected and polished at a degree of polishing 8-10 %. Of them, endorsperm iron rich rice varieties were analysed using ICP-OES. According to results the high iron contents were observed in Suduru samba (4.7 ± 0.58 ppm), Rathu Heenati (4.43 ± 0.75), Kalu Heenati (4.19 ± 0.13), Sudu Heenati (3.71 ± 0.75.) and Basmati 370 (3.71 ± 0.62) on dry weight basis. The bio-availability of five endorsperm iron rich rice varieties, in terms of dialyzability was deduced by in-vitro simulated-gastro intestinal digestion followed by equilibrium dialysis method (Promchan et.al, 2005). Further, the percent bio-availability of some tested rice varieties are given below. Kalu Heenati (8.71 ± 0.94), Suduru samba (7.65 ± 0.18), Basmati 370 (4.78 ± 0.55), Sudu Heenati (2.09 ± 0.49) and Rathu Heenati (1.73 ± 0.03). The present study indicated that Kalu Heenati and Suduru samba are good sources of traditional rice varieties to combat iron deficiency anemia. References Promchan J. and Shiowatana S. (2005). A dynamic continuous-flow dialysis system with on-line electrothermal atomic absorption spectrometric and pH measurements for in-vitro determination of iron bio-availability by simulated gastrointestinal digestion. Anal Bioanal Chem 382: 1360-1367.
Production of Amylase by A. Niger Under Submerged Fermentation Using Pineapple Peel as The Substrate and Its Application in Baking Industry
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Pushpakumara, H.M.P.J.; Weerasooriya, M.K.B.
Starch-degrading amylase was produced by A. niger under submerged condition utilizing pineapple peels as the substrate. Growth parameters were optimized by changing incubation period, pH of the culture media, level of carbon source (dried pineapple peel powder) and additional nitrogen source, in order to get maximum amylase production. Study revealed that the production of extracellular amylase increased with the culture growth and reached to maximum at day 7 in the cultures grown at pH 5.0. Studies with different levels of carbon source indicated that optimum level for carbon source for maximum amylase production was 18 gL-1. Effect of additional nitrogen source on amylase production was also monitored supplementing the growth media with different nitrogen sources such as peptone, gelatin and urea. The result indicates that using gelatin as additional nitrogen source increase the amylase production. Experiments were also carried out to monitor extracellular and intracellular amylase production and the results revealed that extracellular amylase production was found to be higher than that of intracellular. Yield of the enzyme was 8530 units/g of pine apple peel powder. To test suitability of the enzyme for improvement of the quality of bakery products bakery products were prepared by treating the wheat flour dough with different volumes of partially purified enzyme Results showed that Treating 7.7 mL (11.5 UmL-1) partially purified amylase with one kg of wheat flour dough provide better quality product with improved shiny appearance, color, crumb structure, taste and better anti-staling effect than the control.
Production of extracellular amylase by Aspergillus niger under submerged fermentation using jack fruit rag as the carbon source
(Indian Journal of Traditional Knowledge, Vol 19(1), 2020) Piyarathne, S.A.P.M.; Weerasooriya, M.K.B.
Production of extracellular amylase by Aspergillus niger was studied under submerged fermentation using jackfruit rag as the carbon source. Different parameters, such as incubation period, pH of the culture broth and level of substrate were changed to optimise the conditions for amylase production. Maximum enzyme production ~ 8400 units/g was obtained in 5 days old cultures, grown at pH, 6.5 and 30°C with substrate level 20 gL-1. As nitrogen sources NH4Cl, KNO3 casein, peptone and beef extract were tested. Except NH4Cl all other sources enhanced the amylase production. Study on the kinetics of extracellular and intracellular amylase production revealed that extracellular amylase production was always higher than that in intracellular. Crude amylase obtained from culture broth was partially purified by ammonium sulphate fractionation followed by DEAE Cellulose chromatography. Partially purified enzyme exhibited optimum pH and incubation temperature at pH 6 and 60°C respectively and higher thermal and pH stability at 50-60°C and pH 5-7 respectively and enhanced activity with Ca2+. These unique features of the enzyme indicates its suitability for various industrial applications. Shorter incubation period and lower substrate cost offer the potential for inexpensive production of amylase, making the process industrially and economically feasible
Production of extracellular amylase under solid state fermentation using ground nut shell as the substrate and its application in textile and baking industry.
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Apeksha, I.A.U.; Weerasooriya, M.K.B.
Amylases find potential applications in a number of industrial processes such as food, detergent, textiles, brewing and paper industries. Though Amylase can be obtained from several sources, use of microorganisms meet the industrial requirements as it is economical and easy to manipulate microbes to obtain enzymes of desired characteristics. Several methods such as submerged fermentation and solid-state fermentation have been successfully used for amylase production. As the contents of synthetic medium used for amylase production are very expensive, replacing them with available agricultural and industrial wastes would be economically advantageous. Hence, in this study amylase was produced by Aspergillus niger (obtained from the culture collection of Department of Microbiology, University of Kelaniya) under solid state fermentation using dried ground nut shell powder as the carbon source and its potential for using in baking and textile industries were evaluated. Culture conditions were optimised to get maximum amylase production by varying parameters such as incubation period, pH and substrate: moisture ratio. Culture media was supplemented with additional nitrogen source such as Gelatine, (NH4)2SO4, Urea and NH4Cl and amylase production was monitored. Cultures were grown at large scale under optimised conditions. At day 6 mycelia were filtered and culture filtrate was fractionated with ammonium sulphate. Ammonium sulphate fraction (50-75%) which had the highest amylase activity was dialysed and its suitability to use in baking and textile industry was investigated. Bakery products were prepared using the wheat flour dough treated with different volumes of amylase (2.5, 3.00. 3.5, 4.00 and 4.5 ml) and quality of the products were evaluated. To test the possibility of the enzyme produced for use as a desizing agent, gray cotton fabric were immersed (1.5 x 1.5 inch fabric pieces) in pH 5.5 buffer solution supplemented with 500 μl (3.69 U ml-1) and 300 μl (3.69 U ml-1) enzyme respectively. Removal of starch from gray cotton fabric and concomitant release of glucose due to starch hydrolysis was monitored at different time intervals. The optimum incubation period, pH and substrate: moisture ratio for maximum enzyme production were found as day 6, 5.5 and 1:5 respectively. Gelatin and urea addition enhanced amylase production whereas (NH4)2SO4 and NH4Cl showed no significant contribution on the amylase production. Quality of the bakery products such as volume of the product, crust colour and crumb structure were improved with increasing amounts of amylase. Staling was retarded in the samples treated with 4.00 and 4.5 ml amylase with respect to the control. Gray cotton fabric treated with amylase revealed that removal of starch of the fabric and concomitant release of glucose due to starch hydrolysis increases linearly with the increasing time and reached the maximum by 2 hrs. Yield of the enzyme production was ~ 5740 units/g. All these findings suggested that amylase produced by solid state fermentation using ground nut shell as a substrate can be successfully used to improve the quality of bakery products and as an anti-staling agent in baking industry and as a desizing agent in textile industry.
Production of microbial lipase under solid-state fermentation and its application in the detergent industry
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka. p.6, 2019) Chandrasiri, I. W. C. P.; Weerasooriya, M.K.B.
Lipases are the enzymes of choice for laundry detergent industries owing to their triglyceride removing ability from soiled fabrics, which eventually reduces the usage of phosphate-based chemical cleansers in the detergent formulation. In this study, a partially purified extracellular alkaline lipase from Fusarium oxysporum was extracted by solid substrate fermentation using avocado seed powder as the solid substrate. The triglyceride removing ability of the lipase was assessed through a titrimetric assay to use this lipase as an additive in laundry detergents. Optimum growth conditions for maximum alkaline lipase productions on avocado seed powder as solid substrate (particle size 300 microns) was achieved when incubated for 120 hours at initial pH 8, where moisture level (40% w/w) in the presence of Yeast extract or Ammonium Chloride (8% w/w) as nitrogen source, Sucrose (8% w/w) as carbon source enhancer, Castor oil as oil enhancer and Sodium Chloride (4% w/w) as osmoregulator. The effects of selected surfactants, commercial detergents, and oxidizing agents on lipase stability were studied in a preliminary evaluation for its further usage in the industrial environment. Partially purified lipase has shown significant stability in the presence of surfactants, components in commercial detergents, and oxidizing agents (1.0 x 10-3 μmol min-1 lipase activity in the presence of H2O2 (2% w/v) / SDS (4% w/v) / Triton x-100 (10% w/v) / Ca2+ concentration (1000 ppm) and more than 50% residual activity after the incubation of an hour at 30 °C with common household detergents; namely Sunlight powder, Diva, Rin and Vim). Hence, the outcome of the present study opens an avenue for enzyme-based detergent sector for formulation of chemical-free or less chemical detergents with enhanced activity using alkaline microbial lipase