In-situ enriching method and screening method of pullulanase indigenous strains

Abstract

The invention relates to an in-situ enriching method and a screening method of pullulanase indigenous strains. The in-situ enriching method comprises the following steps: burying a matrix to which amylopectin is adhered into soil; enriching; then taking out the matrix; and collecting soil on the surface of the matrix to obtain the strain-enriched soil. The screening method comprises the followingsteps: uniformly mixing the strain-enriched soil and sterile water; centrifuging; performing gradient dilution on an upper suspension; coating a flat separating plate with the gradient diluting solution; culturing; and then identifying. The enriching method has the major characteristic that amylopectin is used as a primary inducing substrate for in-situ enriching the pullulanase indigenous strainsin soil, so that the quantity of pullulanase indigenous populations can be increased in an original ecological environment, and particularly some weak populations with pullulanase activity can be certainly proliferated, and as a result, the detection rate of the target strains can be increased.

Description

technical field [0001] The invention relates to an in-situ enrichment method and a screening method for an indigenous strain producing pullulanase, and belongs to the technical field of bacterial enrichment and screening. Background technique [0002] Microorganisms are an important part of biological resources and material cycles in nature. It is generally believed that the types of microorganisms known to people are only 1%-10% of the actual stock, and some people even think that they are less than 0.1%. It is a long and arduous job. Starch is a polysaccharide compound that is consumed in a huge amount in people's lives. Natural starch is composed of 10%-30% amylose and 70%-90% amylopectin, and the utilization rate of starch mainly depends on the amylopectin The level of utilization. The α-1,6 glycosidic bonds contained in amylopectin are difficult to hydrolyze, which becomes a bottleneck problem in the efficient utilization of starch, and pullulanase exclusively hydroly...

AI Technical Summary

Problems solved by technology

The traditional enrichment method of pullulanase-producing indigenous strains can generally isolate a small number of strains, but the existing problems are also obvious. These deficiencies are concentrated in: (1) The isolation method is too programmed and single, and the isolated strains The repetition rate is extremely high, the diversity is poor, and there are few innovative research results; (2) Enrichment culture for a certain period of time before isolation culture is obviously more targeted than no enrichment, and the effect is slightly better, but in vitro enrichment also has The enriched environment of the sample still has natural defects that are fundamentally different from the natural environment

Any microorganism has its dependent habitat, and the change of habitat will naturally lead to the change of population composition, especially for some weak or rare species, improper treatment is more likely to cause loss during the separation process

[0004] Because the detection rate of pullulanase-producing strain screening in the prior art is not high, even if individual pullulanase-producing strains can be screened out, the diversity of strains is far from rich enough, repeated screening is prominent, and biological activity is common Low, the vast majority of industrial development and application potential is not high

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