利用贝莱斯芽孢杆菌提高红曲米发酵生产中抗黄曲霉污染的能力

Improvement of the resistance to Aspergillus flavus contamination in the fermentation of red fermented rice using Bacillus velezensis

红曲米发酵生产中的污染问题不容忽视,因为这会影响红曲的产量和质量。实验中发现,在用纯种红曲霉发酵红曲米的过程中较易污染黄曲霉,然而,在用市售红曲米作为曲种发酵的过程中污染情况却不经常出现,推测市售红曲米的开放式生产可能给红曲米的发酵过程引入了某种能抑制黄曲霉的菌种。为提高红曲米生产过程抗黄曲霉污染能力,该研究从市售红曲米中分离筛选出1株能够抑制黄曲霉孢子生长的贝莱斯芽孢杆菌Y5菌株,并优化了利用该菌株提高红曲米发酵过程抗污染能力的工艺条件。验证性实验结果表明,在发酵前期微量接种该菌株能够有效减少粗放条件下红曲米发酵过程中黄曲霉污染率,且不会影响红曲霉产色素。因此,在红曲米发酵中可将该菌株作为辅助菌株,以保证发酵的顺利进行。

The pollution problem in red fermented rice(RFR)fermentation cannot be ignored,since it will affect the production and quality of RFR.We found that RFR inoculation fermentation(with Monacus purpureus)was more contaminated by Aspergillus flavus than natural fermentation.However,pollution does not often occur in RFR fermentation when inoculated with commercially available RFR.It was speculated that the open production of commercially available RFR may introduce certain inhibitors that can inhibit A.flavus.To reduce the occurrence of contamination caused by A.flavus,a Bacillus velezensis strain Y5 that can inhibit the growth of A.flavus spores was isolated from commercially available RFR,and the fermentation conditions for improving the resistance to A.flavus contamination in fermentation of RFR were optimized.Confirmatory experiment results showed that inoculation of strain Y5 with small amount in the early stage of RFR fermentation could effectively reduce the contamination rate of A.flavus under extensive condition and would not affect M.purpureus to produce pigment.Hence,this strain can be used as an auxiliary strain in RFR fermentation to ensure the smooth fermentation.