[关键词]
[摘要]
本文以广东客家黄酒酒曲为对象,对黄酒发酵用红曲、麦曲和酒药中的微生物进行分离,探讨了酒曲中微生物产γ-氨基丁酸(GABA)的能力。研究结果表明,从红曲中分离出2株真菌分离物,其中红曲霉1株和酵母1株;从麦曲中分离出7株真菌分离物,其中毛霉1株,曲霉4株,根霉1株和酵母1株;从酒药中分离出6株真菌分离物,其中根霉1株,曲霉4株和酵母1株。通过生化特性研究及序列分析,鉴定出麦曲的曲霉中有1株为米曲霉,酵母为酿酒酵母。将所分离出的菌株分别进行液态发酵,并采用高效液相色谱检测了发酵液中GABA的含量。研究结果显示,从红曲、麦曲和酒药中分离出来的真菌分离物都具有产GABA的能力,不同真菌分离物产GABA的能力不同。其中,根霉和几株曲霉发酵液中GABA含量较高,特别米曲霉,达到40 mg/L以上,毛霉产GABA含量次之,为34.22 mg/L,而酵母产GABA含量最少,为10 mg/L左右。
[Key word]
[Abstract]
Microorganisms present in red jiuqu, wheat jiuqu, and rice jiuqu used for Guangdong Hakka rice wine fermentation were isolated and identified and γ-aminobutyric acid (GABA) production by these microorganisms was studied. The results showed that red jiuqu contained two fungal isolates, a Monascus strain and a yeast strain; wheat jiuqu contained seven fungal isolates, a Mucor strain, four Aspergillus strains, one Rhizopus strain, and one yeast strain; while rice jiuqu contained six fungal isolates, one Rhizopus strain, four Aspergillus strains, and one yeast strain. Analysis of biochemical characteristics and sequence analysis identified one of the Aspergillus strains and the yeast strain isolated from wheat jiuqu as Aspergillus oryzae and Saccharomyces cerevisiae, respectively. The isolates were cultured separately by submerged fermentation and the amount of GABA in the fermentation broth was estimated by high-performance liquid chromatography (HPLC). The results showed that all fungal isolates from red jiuqu, wheat jiuqu, and rice jiuqu could produce GABA, but they had varyed GABA production capacities. Rhizopus and several Aspergillus strains produced relatively high amount of GABA, especially Aspergillus oryzae (more than 40 mg/L), followed by a Mucor strain (34.22 mg/L). Yeast strains produced the least amount of GABA, at approximate 10 mg/L.
[中图分类号]
[基金项目]
广东省产学研项目(2013B090600157);广东省自然科学基金项目(2014A030313592);广东省教育厅重点项目