Large scale production of pectolytic enzyme by solid state fermentation.

Abstract

Pectolytic enzyme was produced on large scale by solid state fermentation using Aspergillus carbanerius CFTRI 1048 strain on wheat bran medium. Effect of fermentation time (up to 25 h), temp. (chamber temp., 26-26.5 degree C, tray temp. 30 degree C), steaming and sterilization of the bran on production of enzyme, and the influence of extraction (enzyme recovery) temp. were assessed. Fermentation for 21 h with a tray temp. of 30 degree C gave max. production of enzyme. Steaming of wheat bran at 15 Pa for 45 min was needed to get good results. Extraction of enzyme by water from mouldy bran at 25-28 degree C and clarification of the enzyme by plate and frame filter press gave satisfactory results. The enzyme could be precipitated using ethanol with a contact time of 5 min (contact times up to 6 h) were tested, and the optimum concn. of ethanol in the alcohol mixture needed for max. recovery was 50% (concn. tried 30-70%). Precipitation at 4 degree C gave 25% more enzyme recovery than at 25-28 degree C. When suspended in buffer of pH 7 the enzyme precipitate lost its activity rapidly at 25-28 degree C and at 4 degree C; the dried powder lost about 6.5% activity in 37 days, vs. 8% for the original extract.