Batch and fed batch production of pectin lyase and pectate lyase by novel strain Debaryomyces nepalensis in bioreactor

The effect of various parameters such as pH, agitation and aeration was studied for maximum production of pectin lyase (PL) and pectate lyase (PGL) by a novel yeast strain Debaryomyces nepalensis in bioreactor. The optimal levels of pH, aeration and agitation rate was found to be 7.0, 300 rpm and 1 vvm, respectively. Under these conditions, D. nepalensis produced 14,200 U/L of PL and 12,000 U/L of PGL corresponding to a productivity of 600 U/L h and 500 U/L h of PL and PGL, respectively. Fed-batch production was studied by feeding inducer (lemon peel), carbon source (galactose) individually and in combination at 12 h of growth for enhanced production of PL and PGL. Combined feeding of inducer and carbon source at 12 h was found to be the best strategy for enhanced production of PL and PGL. Under these conditions, production of PL and PGL increased to 23,300 U/L and 22,400 U/L, respectively which corresponded to a productivity of 728 U/L h of PL and 700 U/L h of PGL, respectively. The production was increased by 1.6- and 1.8-fold and productivity by 1.2- and 1.4-fold for PL and PGL, respectively when compared to batch culture.