Screening of High-yield Pectinase-producing Mold and Optimization of Its Solid-State Fermentation Conditions

Pectinase is a kind of extracellular enzyme from microorganism,and it has been applied in food and beverage production widely.In the experiment,the mould which produces pectinase was screened from rotten Nanguo pear on plate,with selective media.Strains were used in solid-state fermentation,the pectinase activity was determinded with the method of sodium iodide titration.A strain with high ability of producing pectinase was isolated and named as As2.The solid-state fermentation medium components and its fermentation conditions were optimized.The results showed that the optimum medium consists of:42.5 g bran,2.5 g apple promace,2.5%(NH4)2SO4 and 50 mL distilled water.The optimum fermentation conditions were:50 g fermentation medium in 128 mL,inoculation ratio 20%,pH=4.0,temperature 30 ℃ for 96 h.The highest yield was up to 6 635 U/g.