Efficient production of protopectinases by Bacillus subtilis using medium based on soybean flour

We have developed a culture system for efficient production of protopectinases (PPases) by Bacillus subtilis. PPase shows the pectin-releasing activity and is expected to be utilized in the enzymatic cotton scouring. B. subtilis IFO3134 was cultivated using defatted soybean flour as a main component of culture media. This strain produced three different types of PPases, namely, PPase-C, -N and -R performing endo-arabinase activity, pectate-lyase activity and pectin-lyase activity, respectively. The effects of alkaline solubilization and autoclave treatments to extract nutrients from soybean flour and initial soybean flour concentration (20-80g/l) on production of PPases in batch fermentation were investigated. Alkaline solubilization of soybean flour with NaOH remarkably reduced enzyme productivity. In addition, a higher initial concentration of soybean flour reduced the enzyme productivity of cells. The pectin-releasing activity was the largest and reached up to 2200-2400U/ml, when the culture medium containing an initial soybean flour concentration of 40g/l was autoclaved for 45-60min without alkaline solubilization treatment.