Study on Isolation of A high-yield pectinase strain and Optimization of Fermentation Conditions

[Objective]The aim was to screen new efficient microbial strain for producing pectinase and provide the basis for optimizing the bio-degumming technology of ramie.[Method]Strains producing pectinase from ramie retting mud,putrefactive ramie and ramie planting soil were isolated,the high-pectinase strain with larger transparent circle which grew faster on pectin plate media was screened and re-screened. The initial pH value of fermentation medium,fermentation temperature,fermentation time,carbon source and nitrogen source of fermentation medium were optimized.[Result]Eight high-yielding strains had been obtained,of which HY11 had the highest activity in producing pectinase. Under the best fermentation conditions of pH value of 6,temperature of 35℃,time of 30 h,2.0%rapeseed cake as carbon source, 1.0%NH_4H_2PO_4 as nitrogen source of fermentation medium,the activity of pectinase reached 453 U/ml,which increased 33.52%compared with that before optimization.[Conclusion]High-yielding strain of pectinase named HY11 had been obtained,and its enzyme activity were considerably increased under the optimized conditions.