Indian Journal of Biotechnology Vol 3, January 2004, pp 65-69 Optimization of process parameters for production of lipase in solid-state fermentation by newly isolated Aspergillus species K Adinarayana, K V V S N Bapi Raju, M Iqbal Zargar, R Bhavani Devi, P Jhansi Lakshmi and P Ellaiah* Pharmaceutical Biotechnology Division, Department of Pharmaceutical Sciences, Andhra University, Visakhapatnam 530 003, India Received 15 November 2002; accepted 21 April 2003 Of the 34 fungal species, isolated from a number of oily substrates, 9 exhibited lipase activity. AU 15, identified as Aspergillus sp., was found to be excellent lipase producer in submerged fermentation and was selected for solid-state fer- mentation (SSF). Among substrates like oil cakes of coconut, groundnut and sesame, wheat rawa, bombay rawa and soya beans (crushed), wheat rawa showed the highest lipase activity. The maximum enzyme yield (1934 U/g) was obtained with basal medium containing wheat rawa, olive oil and corn steep liquor, at 80% moisture content, pH 7.0 and 96 hrs incubation. Keywords: lipase; Aspergillus species; solid state fermentation (SSF); submerged fermentation (SmF) Introduction Lipases (EC 3.1.1.3) hydrolyse triglycerides into diglycerides, monoglycerides, glycerol and fatty ac- ids. They are widely distributed in animals, plants and microorganisms. Fungal lipases have received atten- tion because of their potential use in food processing, pharmaceuticals, cosmetics, detergents and leather industry 1 . New applications, such as the resolution of racemic mixtures to produce optically active com- pounds, should also arise from the stereo specific act- ing properties of some lipases 2 . Solid-state fermentation (SSF) processes are of special economic interest for countries with an abun- dance of biomass and agro-industrial residues. The reports on SSF system include lipase production from Aspergillus niger using gingelly oil cake as substrate 3 , the feasibility of obtaining lipase with Rhizopus dele- mar growing on a polymeric resin 4 , production of li- pase by A. oryzae with different solid substrates 5 and production of lipase by Penicillium restrictum 6 . Li- pase synthesis 7 was optimized by the yeast Candida rugosa in SSF and the C/N ratio of medium was found to be an important parameter for lipase produc- tion. On comparing 8 the production of lipase by Peni- cillium candidum in SmF and SSF, SSF process was found superior. The SSF offers high productivity, less capital in- vestment and relatively easy recovery of extra cellular enzymes compared to SmF 9-12 . In the present investi- gation, screening was carried out to look for new po- tential microbial source for lipases. This paper reports the production of lipase by SSF using Aspergillus sp. (AU15), isolated from oily substrates and optimiza- tion of various production parameters. Materials and Methods Screening for Lipase Producing Fungi by Agar Plate Tech- nique Different oily substrates used for the isolation of li- pase producing fungi include oil cakes of coconut, groundnut and sesame, fungal infected coconut (wet kernel), castor oil soaked cloth, soil from sesame oil mill and spoiled bread. The substrates were inoculated into yeast extract malt extract (YEME) broth for the enrichment. To 5 ml YEME broth in test tube, small amount of each oily substrate was added separately and incubated for one week. From the broth, serial dilutions were made and 1 ml of the diluted sample was added to 50 ml of molten potato dextrose agar (PDA) medium contain- ing 50 ug/ml of rifampicin and poured into 15.24 cm dia petriplates. The plates were incubated at 30 o C for 7 days; the discrete colonies were picked up, trans- ferred onto PDA slants and incubated at 30 o C for 3 days. These isolates were tested for their lipolytic ac- tivity on agar plates 13 with tributyrin as substrate and victoria blue as indicator 14,15 . —————— *Author for correspondence: Tel: 91-891-2701852; Fax: 91-891-2755547 E-mail: adikunamneni@rediffmail.com