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Yeast’s Effect on Soil
- Oct 25, 2018 -

With the development of science and technology, yeast has been applied more and more, and the use of yeast technology to repair contaminated soil is an effective method.Yeast resources are very rich, and metabolic pathways are diverse, and the operating methods are relatively mature, which has great potential to repair the soil with multiple pollution.Yeast technology has made great breakthroughs in eliminating pesticides, herbicides, polycyclic aromatic hydrocarbons and heavy metals in contaminated soil.

Remediation of pesticide contaminated soil

Organochlorine pesticides mainly include HCH (HCH), DDT (DDT), chlordane and heptachlor, etc., which are highly residual pesticides used on a large scale in the 20th century, with high toxicity, difficult degradation and long metabolic cycle.If HCH is decomposed into 95% in soil for a maximum of 20 years, the chemical properties of DDT are also relatively stable. Although it has been banned for nearly 30 years, there are still a large number of residues in the environment.Organochlorine pesticides have certain volatility and strong lipid solubility, and can be enriched in organisms through the food chain, causing harm to ecosystem and human health.

Yeast degradation plays an important role in the process of eliminating organochlorine pesticides.Taking HCH as the only carbon source, three strains of bacteria, including bacillus, achromia and pseudomonas, were successively obtained, with the degradation rates of 59.6%, 56.9% and 56% for the total HCH, and 55.9%, 57.6% and 56.9% for HCH.One strain of oligotrophomonas D1 was screened from DDT contaminated soil by experts, and its degradation rate of DDT degradation for 10d was 69%.

Organophosphorus pesticide is the main category of pesticides, which has a significant impact on ecosystem such as soil respiration.Organophosphorus pesticides mainly include methamidophos, dichlorpyrifos, chlorpyrifos and dichlorvos.There have been many studies and reports on the degradation of organophosphorus pesticides by yeasts at home and abroad. At present, many degradation strains have been isolated, various degradation enzymes have been purified, and many degradation enzyme genes have been cloned and expressed.

Oct.25, 2018