关键词: 米根霉, 废菌体, 壳聚糖, 膜性能

Abstract: Preparation of chitosan from waste biomass of lactic acid fermentation and its membrane characteristics were investigated. The results indicated that 100 g/L of glucose was fermented by R. oryzae for 48 h, then 51.59 g/L of lactic acid and 4.36 g/L of biomass were obtained, and chitosan extraction yield about 13.5 % of the cell dry weight was achieved . The deacetylation degree of R. oryzae chitosan was 89.4%, which was higher than that of commodity chitosan(86.6%). The viscosity of 20 g/L of R. oryzae chitosan solution was 5.13 mPa·s, and the molecular weight of R. oryzae chitosan(M_w=68.61 ku, M_n=48.13 ku) was similar to commodity chitosan(M_w=70.17 ku, M_n=53.53 ku), which was extracted from crab shell. The results of FT-IR proved that the R. oryzae chitosan was similar to commodity chitosan. When the thickness of membrane was (0.025±0.002)mm,the modulus of elasticity of R. oryzae chitosan membrane and commodity chitosan membrane were 42.72 and 14.64 N/mm², respectively. The tensile strengths were 132.31 and 44.13 N/m, respectively. The water absorption rates were 52.90% and 175.80%, respectively. The temperatures at maixmum decomposition rate were 281.4 ℃ and 285.4 ℃, respectively. The onset and final temperature of decomposition were different. The film-forming performance of R. oryzae chitosan was better than that of commodity chitosan, and the R. oryzae chitosan was suitable for food packaging film preparation.

Key words: R. oryzae, waste biomass, chitosan, membrane performance