摘要
聚谷氨酸(γ-Polyglutamic acid,γ-PGA)是自然界中微生物发酵产生的一种无毒的水溶性多聚氨基酸,是由L-谷氨酸和D-谷氨酸通过脱水缩合而成的一种高分子聚合物,具有良好的延展性、生物相容性、稳定性与吸水性等特点。本试验从发酵豆制品中分离并筛选产γ-PGA的菌株,结合形态学观察、生理生化鉴定及16S r RNA基因序列分析对菌株进行鉴定,并通过单因素试验与正交试验对发酵条件进行优化。为提高大豆幼苗低温耐受性,将菌株的γ-PGA发酵液应用于大豆盆栽中,初步探究发酵液对大豆幼苗耐寒性的影响。结果表明:分离得到一株产γ-PGA的菌株,命名为YW-5,属于贝莱斯芽孢杆菌(Bacillus velezensis);通过优化获得最优发酵条件为蔗糖4 g·L^(-1)、牛肉膏1 g·L^(-1)、味精3.5 g·L^(-1)、KH_2PO_(4 )0.03 g·L^(-1)、p H5.2,优化后γ-PGA产量为5.10 g·L^(-1);盆栽试验初步证明叶面喷施发酵液能够有效降低低温胁迫下大豆幼苗叶片的MDA(丙二醛)含量,增加大豆幼苗叶片的POD、CAT活性以及增强大豆幼苗的根系活力,具有良好的应用潜力。
γ-Polyglutamic acid(γ-PGA)is a non-toxic water-soluble polyamino acid produced by microbial fermentation in nature.It is a kind of polymer formed by the condensation of L-glutamic acid and D-glutamic acid through dehydration.It has the characteristics of good ductility,biocompatibility,stability and water absorption.In this experiment,γ-PGA producing strains were isolated from fermented soybean products produced in the laboratory by screening media,and the strains were identified by morphological observation,physiological and biochemical identification and 16S rRNA sequence analysis.The fermentation conditions were optimized by single factor test and orthogonal test.In order to improve the low temperature tolerance of soybean seedlings,the gamma-PGA fer⁃mentation solution of the strain was applied in soybean pot,and the effect of the fermentation solution on the cold tolerance of soybean seedlings was preliminatively investigated.The results showed that a γ-PGA producing strain was isolated,named YW-5,belonging to Bacillus velezensis.The optimal fermentation conditions were 4 g·L^(-1) su⁃crose,1 g·L-1 beef paste,3.5 g·L^(-1) monosodium glutamate,0.03 g·L^(-1) potassium dihydrogen phosphate and 5.2 pH.After optimization,the yield of γ-PGA was 5.10 g·L^(-1).Pot experiment preliminatively proved that leaf spraying fer⁃mentation liquid can effectively reduce the MDA content of soybean seedlings under low temperature stress,in⁃crease the POD and CAT activities of soybean seedlings,and enhance the root vitality of soybean seedlings,which has good application potential.
作者
魏莹
李达
过杭剑
孙圣凯
李宇欣
孙冬梅
WEI Ying;LI Da;GUO Hang-jian;SUN Sheng-kai;LI Yu-xin;SUN Dong-mei(College of Life Science and Technology of Heilongjiang Bayi Agricultural University/Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Agro-Waste in Cold Region,Daqing 163000,China;Key Laboratary of Low-Canbon Green Agriculture in Northeater China,Ministry of Agriaclture and Rural Affairs,Daqing 163000,China)
出处
《中国油料作物学报》
CAS
CSCD
北大核心
2024年第6期1372-1381,共10页
Chinese Journal of Oil Crop Sciences
基金
中国科学院战略性先导科技专项项目(XDA28030203)。
作者简介
魏莹(2001-),女,硕士研究生,研究方向为微生物学,E-mail:2686532199@qq.com;通讯作者:孙冬梅(1970-),女,教授,博士,主要从事应用微生物研究,E-mail:sdmlzw@126.com。
