Optimizing Fermentation Conditions Of Alkaline Pectinase

In this paper, the growth morphologies of laboratory alkaline pectinase producing strains Paenibacillus pabli WZ008was studied. We found that the inoculation culture of the bacteria has flocculence and turbidity two forms.Fermentation production of alkaline pectinase with the two forms of the inoculation culture, the results obtained fermentation enzyme activity of the flocculent inoculation culture was42U/mL,5times more than the turbid one. In order to get the flocculent inoculation culture, the culture medium composition and culture conditions were optimized.Obtained that let the strain at4℃refrigerate for3weeks then inoculate it in the optimized culture medium(yeast extract20g/L, peptone lOg/L, soluble starch lOg/L, NaCl2g/L, K2HPO44g/L pH9.0), the flocculent inoculation culture can be got stably at above optimized method.On the shaking flask level, the flocculent inoculation culture was optimized with different fermentation media and condition.Based on primary medium, the effects of carbon, nitrogen sources, inorganic salts, pectin,fermentation time and initial pH were investigated. The optimized fermentation medium contained:yeast extract1%, β-cyclodextrin0.4%, soybean meal1%, pectin0.8%, CaCO30.7%,(NH4)2SO40.4%.The optimized fermentation condition as follows:volume of medium50ml/500ml, temperature30℃, initial pH7.8, inoculation ratio15%, time60h,The yield of alkaline pectinase was107U/mL,2.5times than unoptimized.Take the optimized data in the flask as the theoretical basis, flocculent inoculation culture enlarged culture and fermentation in5L fermentor were studied. Obtained by controlling the pH as8.0can contribute to the inoculation culture grow into a flocculent form while increasing the biomass,and during the fermention process control dissolved oxygen(DO) at25%, while control the fermentation medium pH not less than7.0with NaOH is favor to the production of alkaline pectinase, the maximum enzyme activity reached120U/mL...