产聚谷氨酸耐盐碱芽孢杆菌的筛选及改良砒砂岩土壤的作用

Screening of polyglutamic acid producing and saline-alkali-tolerant Bacillus strains and the effect on improving Pisha sandstone soil

筛选产聚谷氨酸的耐盐碱芽孢杆菌并探究其发酵液对植物和砒砂岩土壤的改良作用,为解决砒砂岩土壤植物难以生长、水土流失严重等问题提供思路。从砒砂岩、黄棕壤、盐碱土中筛选得到耐盐碱芽孢杆菌且高产聚谷氨酸;采用盆栽试验,通过分析黑麦草的生物量,土壤的保水率、渗水率、酶活性、pH、阳离子交换量、有机质、有效磷和速效钾及多糖含量来评价菌株对黑麦草生长及砒砂岩土壤肥力的影响。筛选到两株聚谷氨酸产量较高的耐盐碱芽孢杆菌YF20和YG35,分别属于Bacillus zanthoxyli和Priestia megaterium。与未接菌加生物炭处理相比,菌株YG35能显著提高黑麦草鲜重33%,土壤多糖含量40%、有机质含量23%、有效磷含量31%、蔗糖酶活性17%;菌株YF20能显著提高土壤阳离子交换量7.2%、有机质含量15%、保水率2.2%,渗水率减少2.74%。两株聚谷氨酸产生菌均能提高砒砂岩土壤质量,促进植物生长,为微生物改良砒砂岩土壤提供理论依据。

This research was carried out to screen saline-alkali-tolerant Bacillus sp.producing polyglutamic acid and explore the improvement effect of its fermentation broth on plants and Pisha sandstone soil,enrich the theory of soil improvement by microorganisms,and promote the development of microbial ecology.Taking salt tolerance,alkali tolerance and polyglutamic acid yield as screening indexes,Bacillus was screened from existing soil samples in the laboratory.A pot experiment was conducted to evaluate the effects of strains on ryegrass growth and Pisha sandstone soil fertility by analyzing ryegrass biomass,soil water retention,water permeability,enzyme activity,soil pH,cation exchange capacity,organic matter,available phosphorus,available potassium and polysaccharide content.Two strains of saline-alkali-tolerant strain YF20 and YG35 with high polyglutamic acid production were screened,which belonged to Bacillus zanthoxyli and Priestia megaterium respectively.Strain YG35 significantly increased the fresh weight of ryegrass by 33%,soil polysaccharide content by 40%,organic matter content by 23%,available phosphorus content by 31%,and sucrase activity by 17%than biochar,respectively.Strain YF20 significantly increased soil cation exchange capacity by 7.2%,organic matter by 15%,water retention rate by 2.2%,and water permeability by 2.74%than biochar,respectively.Two strains of polyglutamic acid producing bacteria can improve the quality of Pisha sandstone soil and promote plant growth,which provides a theoretical basis for microbial improvement of Pisha sandstone soil.