Production of an extracellular lipase by Candida utilis NRRL-Y-900 using agro-industrial by-products

Aim: To screen various yeast cultures and agro-industrial by-products and optimization of fermentation conditions for the microbial production of extracellular lipase under solid state fermentation technique. Material and Methods: Various yeast cultures including Candida lipolytica NRRL-Y-1095, Candida utilis NRRL-Y-900, Candida tropicalis NRRL-Y-1552, Saccharomyces cerevisiae IIB-1 were screened by culturing on agro-industrial by-products under batch culture using solid state fermentation in 250 mL Erlenmeyer flasks. The medium was supplemented with various nitrogen sources (both organic and inorganic) and metal ions. Results: Candida utilis NRRL-Y-900 showed the highest enzyme production on soybean meal. Various particle sizes of substrate and moistening agents were also optimized for the maximum lipase synthesis. The optimum temperature and pH for the accumulation of enzyme by Candida utilis NRRL-Y-900 was 30 degrees C and 6.5, respectively. The fermentation time of 60h was suitable for the maximum enzyme production by using 7.5% inoculum of 24h old yeast culture. The optimal medium composition consisted of 2% (w/v) meat extract, 0.4% (w/v) ammonium sulphate and 5mM Fe+2. The maximum extracellular lipase production was 3.96 +/- 0.09 U. Conclusion: The results obtained during the study are significant for, to our knowledge, it is the first report regarding the utilization of soybean meal by C. utilis NRRL-Y-900 to accumulate lipase under optimized conditions and solid state fermentation.