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Item 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 feasibleItem 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.Item 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 lipaseItem 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.Item 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.Item Zinc content and prediction of bio-availability of zinc in some locally grown rice (Oryza sativa L.) varieties in Sri Lanka(National Science Foundation of Sri Lanka, 2016) Herath, H.; Rajapakse, D.; Wimalasena, S.; Weerasooriya, M.K.B.Rice is the staple food in Sri Lanka and the country has a large number of traditional and improved rice varieties. Since their zinc content and bio-availability has not been studied systematically, the present study focused on the zinc content in some traditional rice varieties with high demand and also some improved rice varieties, and their predictable bioavailability. Thirty nine rice varieties from Bombuwala and Bathalagoda Regional Agricultural Research and Development Centres, grown during Yala (March - August, 2006) and Maha (September - March, 2006 ⁄2007) seasons were analysed for stable high zinc rice varieties. Mean zinc content (mg/100 g, on dry weight basis) in the varieties from Bathalagoda varied from 2.17 (Masuran) to 4.49 (Wanni Dahanala), while in the varieties from Bombuwala it varied from 2.46 (Bg 352) to 3.71 (Dahanala) with average values of 3.19 ± 0.55 and 3.11 ± 0.32, respectively. Overall mean zinc content (mg/ 100 g, on dry basis) in the two locations varied from 2.51 (Masuran) – 3.91 (Kalu Bala Wee) with an average value of 3.18 ± 0.45. The mean zinc contents varied significantly (p ≤ 0.05) with varieties. A significant variation (p ≤ 0.05) was observed with respect to the site, season, variety, site*var and ses*var in two way ANOVA, while site*ses*var showed a significant variation in three way ANOVA. The reduction of zinc and phytic acid contents in the selected fifteen polished rice varieties (at polishing rate 8 – 10 %) were 18.2 – 60.7 % and 18.8 – 40.8 %, respectively and no significant correlation was observed between zinc and phytic acid. A moderate bio-availability of zinc was shown by the molecular ratio of zinc:phytic acid and these values ranged from 8.3 – 12.5 and 9.3 – 18.9 in brown rice and polished rice, respectively.Item Studies on rice bran lipase to investigate its potential to use as an additive in detergent formulation(Sri Lanka Association for the Advancement of Science, 2013) Singaram, I.; Weerasooriya, M.K.B.Item 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.Item Use of rice bran Lipase to enhance washing performance of commercial detergents(Sri Lanka Association for the Advancement of Science, 2009) Weerasooriya, M.K.B.; Tilakarathne, M.N.S.Item Rubber seed Lipase as a possible candidate in bio-detergent industry(Sri Lanka Association for the Advancement of Science, 2009) Weerasooriya, M.K.B.; Gunasekara, O.S.W.