Lipase production by Aspergillus terreus using mustard seed oil cake as a carbon source

Abstract

An extracellular lipase-producing fungus was isolated from the garden soil of the Post Graduate Department of Botany, Utkal University, Bhubaneswar, Odisha, India and identified as Aspergillus terreus. The A. terreus strain isolated was found to be capable of producing lipase in both solid state culture and liquid static surface culture. Experiments aimed at evaluating and improving the production of lipase and at studying the culture conditions revealed that of the many different materials tested as substrates, mustard oil cake (MoC) was the best substrate for extracellular lipase production. A correlation was found between the lipase production profile and biomass development. In a study aimed at continuing this line of research, we have investigated the influence of various culture conditions, such as environmental (i.e. temperature and pH), nutritional (i.e. carbon, nitrogen, metal ions, vitamins, combined agro-wastes and growth regulators) and other factors (inoculum size and initial moisture content) on the production of lipase by A. terreus in solid state and liquid static surface cultures. We observed that optimum lipase biosynthesis occurred under the following conditions: initial pH of 6.0, 30 °C, a 96-h incubation, lactose and ammonium persulphate as the carbon and nitrogen source respectively and 80 % moisture content. Changes in the vitamins (vitamin C, riboflavin, folic acid and vitamin E) and growth regulators (gibberellic acid, kinetin, 6-benzylaminopurine and 2,4-dichlorophenoxyacetic acid) did not support enhanced lipase production. MoC and neem oil cake (NoC) added to the media at a ratio of 9:1 respectively, supported maximum lipase production. Based on these results, we concluded that controlling the various culture conditions, supplementing MoC as a substrate and nutrient source modification of the medium can spectacularly enhance lipase biosynthesis by A. terreus.