A method for screening and isolating sulfate-reducing bacteria using an improved stacked plate method

Abstract

The invention relates to a method for screening and separating sulfate-reducing bacteria by using an improved repeat dish plate method. The method comprises the steps that firstly, microorganisms in soil are transferred and screened through a sulfate-reducing bacteria liquid enrichment medium; secondly, bacterial strains are cultured by using the improved dilution coating-repeat dish sandwich method and the screening medium; thirdly, the bacterial strains obtained in the second step are separated and purified by using a common repeat dish double-layer plate method; fourthly, the bacterial strains are preserved and cultured in a preservation and culture medium. By means of the method, the defects that in the prior art, bacteria liquid cannot uniformly spread and percolate on a first-layer plate, the growth of the bacteria liquid is not benefited after the bacterial liquid is diluted, the bacterial liquid is prone to up-down overlap, and even other bacteria grow are overcome, and the method has the advantages that the material is simple and convenient to use, the screening efficiency is high, the screening period is short and the conversion rate of the bacteria strains is high.

Description

technical field [0001] The invention belongs to the technical field of environmental microorganisms, and in particular relates to a method for screening and separating sulfate-reducing bacteria by using an improved stacked plate method. Background technique [0002] At present, the use of high-tech biotechnology such as bioengineering to cultivate plants and soil microbial super-engineering bacteria that can fix heavy metals, and to apply them to soil pollution control is currently the most advanced research in environmental science, environmental engineering, plant physiology, and microbiology. One of the active frontiers. Microorganisms can convert heavy metals through redox, methylation and demethylation, and convert toxic substances into forms that are not available to animals and plants. [0003] Sulfate-Reducing Bacterium (SRB for short) can reduce sulfur oxides such as sulfate, sulfite, thiosulfate, and elemental sulfur to form sulfur ions in nature. Due to the solub...

AI Technical Summary

Problems solved by technology

The disadvantage of the dilution shaking tube method is that it is difficult to observe and pick colonies. The Hungate rolling tube method and the method of using anaerobic equipment are restricted by technical methods and equipment material costs. Between the upper and lower layers of medium, it creates a relatively anaerobic environment, so that SRB can grow in the gap

[0005] However, the traditional stacked-dish interlayer method generally cannot evenly spread and infiltrate bacteria on the first plate, and the oxidation-reduction potential of the bacterial solution will increase with the increase of the dilution factor after dilution. For the sulfate-reducing bacteria poor growth

In addition, during the pouring process of the second layer of agar layer, the diluent will diffuse into the second layer, resulting in the phenomenon that colonies overlap up and down and even appear on the surface of the second layer where miscellaneous bacteria grow. Screening colonies poses certain difficulties