微生物降解葡萄皮单宁研究

摘要

In this paper, Penicillium sp. and Aspergillus oryzae were selected as biological strains to degrade grape pomace tannins to reduce its molecular weight and polymerization. The conversion and yield of catechin were chosen as index. The effects of carbon source, nitrogen source, culture time, culture temperature, pH and mass concentration of the tannins on the degradation of the tannins were studied. The results show that adding carbon and nitrogen sources is beneficial to the growth of microorganism strains. The incubation time is a key parameter influencing the intermedi-ate degradation products of the condensed tannins. The incubation temperature, pH and mass concentration of the tan-nins have different effects on the activity and degradation ability of the strains. The degradation ability of P. sp. strain is better than A. oryzae strain. The optimal degradation condition of P. sp. strains is that the mass concentration of the tannins in induced medium is 12.5 g/ L;the pH is 6.5;and the strains is cultured in shaking table at 28℃ for 24 h. The maximum mass concentration of the catechin is 0.32 mg/ mL, and the maximum conversion is 52. 3%. The opti-mal degradation condition of A. oryzae strains is that the mass concentration of the tannins in induced medium is 10. 0 g/ L;the pH is 6. 5;and the strains is cultured in shaking table at 28℃ for 36 h. The maximum mass concentration of the catechin is 0. 16 mg/ mL, and the maximum conversion is 32. 2%. It is possible to control the chemical composition of the grape pomace tannins and decrease its molecular weight and polymerization by microbial degradation method.%为降低葡萄皮单宁的分子量和聚合度,选取青霉(Penicillium sp.)和米曲霉(Aspergillus oryzae)为微生物菌株对葡萄皮单宁进行生物降解.以儿茶素的生成量和转化率为指标,分析碳源、氮源、时间、温度、pH和诱导培养基中单宁质量浓度对降解效果的影响.结果表明:外加碳源和氮源有利于青霉和米曲霉菌株的生长;时间为葡萄皮单宁降解得到不同中间产物的关键参数;温度、pH和葡萄皮单宁的质量浓度对菌株活性和降解能力均有不同程度影响;青霉对葡萄皮单宁的降解效果好于米曲霉.青霉最佳降解条件:培养时间24 h,温度28℃,pH 6.5,单宁质量浓度12.5 g/L,儿茶素最大生成质量浓度0.32 mg/mL,转化率52.3%;米曲霉最佳降解条件:培养时间36 h,温度28℃,pH 6.5,单宁质量浓度10.0 g/L,儿茶素最大生成质量浓度0.16 mg/mL,转化率32.2%.因此,可通过生物降解法调控葡萄皮单宁的化学组成,适当降低单宁的分子量和聚合度.