基于农用酵素生产降本增效的复合菌系筛选及接种效果研究

Study on screening and inoculation effect of composite strains based on cost reduction and efficiency improvement of agricultural Jiaosu production

为开发低成本、高效率的农用酵素接种菌剂,并探明其作用效果,采用限制性继代培养法,分别利用改良MRS(M)和红糖(H)培养基对酵素微生物进行培养,获得2组乳酸菌复合菌系,分别命名为MLA 1和HLA 1,并将这2种菌系接种到农用酵素发酵体系中,测定继代培养体系的pH和有机酸含量,复合菌系的微生物结构和多样性,接种后发酵液的细菌和乳酸菌数量、pH、有机酸含量及对尖孢镰刀菌(Fusarium oxysporum)的抑制效果等指标。结果表明:MLA 1和HLA 1均主要由乳酸菌属(Lactobacillus)和醋酸菌属(Acetobacter)构成;在限制性培养中,MLA 1相比HLA 1产酸升高40%,乳酸菌丰度升高5%,而HLA 1的Chao、Faith和Shannon指数高于MLA 1,表明其微生物多样性更高;接种到酵素发酵体系中,MLA 1和HLA 1的接种分别使酵素发酵过程的乳酸产量升高251%和295%,乳酸菌在细菌中的占比分别升高12%和16%,对尖孢镰刀菌的抑菌率均升高15%以上。综上,HLA 1和MLA 1的接种效果接近,考虑到成本,利用红糖培养基筛选复合菌系(HLA 1)具有更高的应用价值,有助于在农用酵素大规模生产中的降本增效。

To develop low cost and high efficiency agricultural Jiaosu inoculants and investigate their effects,the restricted continuous subculture method was adopted to culture Jiaosu microorganisms by using the improved MRS(M)and brown sugar(H)medium,respectively.Two groups of lactic acid bacteria composite strains named MLA 1 and HLA 1 were obtained.The two groups strains were inoculated into agricultural Jiaosu fermentation system.After the restricted continuous subculturing,the volatile fatty acid concentration,pH and the microbial structure of the strains were measured.The copies of 16s rRNA gene bacteria and lactic acid bacteria,pH,volatile fatty acid concentration and the inhibition effect on Fusarium oxysporum of inoculated Jiaosu were determined.The results showed that:Both MLA 1 and HLA 1 were mainly composed of Lactobacillus and Acetobacter.In the MLA 1 culture,the acid production increased by 40%and lactobacillus abundance by 5%compared with those of HLA 1.The Chao,Faith,and Shannon indices of HLA 1 were all higher,indicating higher microbial diversity.After inoculation with MLA 1 and HLA 1,the lactic acid yield of Jiaosu increased by 251%and 295%,respectively,the proportion of lactic acid bacteria in the bacteria increased by 12%and 16%,respectively,and the inhibitory rate against F.oxysporum increased by more than 15%.In conclusion,the inoculation effects of HLA 1 and MLA 1 are similar.Considering the cost,the brown sugar medium is more suitable for screening inoculants and conducive to achieve the low cost and high quality during the large-scale production of agricultural Jiaosu.