γ-Polyglutamic acid(γ-PGA)owns such biological properties as moisturizing,frost resisting,and film formation.Besides,it also functions to preserve flavor,retain water,and absorb heavy metals.Microbial fermentation stays as a primary means of γ-PGA production.With fermented bean curd,pickled Chinese cabbage,and soybean paste as the objects,this study obtained first single colony using plate streaking approach and then determined γ-PGA content in different fermentation broths with ultraviolet spectrophotometry to get the more productive strains of γ-PGA.The resulting yield was 43.96 g/L.The strains further received spore and Gram staining to determine whether they were Bacillus pumilus under molecular identification.Sin-gle-factor and orthogonal tests were employed to figure out the optimal parameters for solid-state fermentation of the strains.The parameters are as follows:heavily ground soybeans(at 70％),a bacterial liquid's inoculum size of 2％,culture time of 42 h,a yield of 118.19 g/L.Rough γ-PGA product resulted from ethanol precipitation,dialysis,and low-temperature freezing and drying of the supernatant.The moisture retention and oxidation resistance performances of the rough γ-PGA were investi-gated through an observation of its liquid volatility.The results indicate the moisture retention rate of the rough γ-PGA rises slightly with growing concentration.When γ-PGA dosage is 80 μg/mL,the moisture retention rate and DPPH removal rate at-tain 98.95％and 75.35％,respectively.The research findings hereby may provide a theoretical basis for the solid-state fer-mentation of γ-PGA and plant-based moisturizer development and utilization.
关键词
γ-聚谷氨酸/固体发酵/短小芽孢杆菌/分离纯化/保湿性
Key words
γ-polyglutamic acid/solid state fermentation/Bacillus pumilus/separation and purification/moisture retentiveness
维普
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