Effects Of Heavy Metals Copper And Zinc On Microorganisms And Redoxase Enzymes Activity During Composting

Pile of corruption process is advanced under the affection of the microbial and enzyme, the existence of heavy metals in the microorganism of materials is likely to produce certain poisonous effect of the enzyme activity, also is restrained. This study focused on the effects of heavy metals on microorganisms and redoxase enzymes activity during composting. Based on the summary of the results of previous research in related fields, pig manure and wheat straw were used as the main experimental materials. The changes of polyphenoloxidase and dehydrogenase activities, and the changes of composting temperatures, pH and humic acid E4/E6 of composting materials and in the process of corruption in different periods stockyard microbial communities change during aerobic fermentation in thermophilic aerobic state were studied in this paper.The research results were as follows:1. Effects of heavy metals Cu on oxidoreductase activity during agriculture wastes composting(1) In composting process, different concentrations of heavy metals Cu have different influence of the physicochemical property of compost. Judging from the temperature changes, the temperature of the treatment 100 mg·kg^-1 increased more quickly compared with CK and 500 mg·kg^-1, with higher temperature and longer high temperature duration, and achieved the requirement of the harmlessness. Judging from the pH changes, the pH value of the CK was lower that the other treatments, that would be bad for degradation of glucose and protein, metabolism of the microbe. pH value too high of treatment 500 mg·kg^-1, which would be easy to loss nitrogen . Concentration heavy metals Cu treatments 100 mg·kg^-1, the pH of stacking between 7 and 8, which would be beneficial to the growth of microorganism and the breakdown of proteins. Judging from the change of the E4/E6, it is would be more beneficial which content Cu of 100 mg·kg^-1 to the mineralization budding and corruption of organic material than the other.(2) Judging from the activity of polyphenol oxidase in composting process, the activity of polyphenol oxidase of windrow which content Cu of 100 mg·kg^-1 is the highest, it is 19.34 mg moshizisu·g^-1·h^-1,71.77% higher than CK, 1.84% higher than that content Cu of 500 mg·kg^-1. (3) Judging from the activity of dehydrogenase, the windrow which content Cu of 100 mg·kg^-1 changes heavily, and shows some instability, meanwhile, the average activity of dehydrogenase is the hightest, it is 5.09 Tfug/g·h, 2.51 times of CK, 3.02 times of the windrow which content Cu of 500 mg·kg^-1, is beneficial to the redox of windrow.2. Effects of Zn on oxidoreductase activity during agriculture wastes composting(1) In composting process, different concentrations of heavy metals Zn have different influence of the physicochemical property of compost. Judging from the temperature changes, low Zn processing (Concentration heavy metals Zn treatments 0 mg·kg^-1,300 mg·kg^-1,600 mg·kg^-1,900 mg·kg^-1 ), the temperature increased rapidly, the thermophilic phase was long, and the requirement of the harmlessness could be achieved.Judging from the pH changes, Concentration heavy metals Zn treatments 300 mg·kg^-1,600 mg·kg^-1,900 mg·kg^-1have stronger control ability on pH, can reduce nitrogen losses;Judging from the E4 / E6 changes, Concentration heavy metals Zn treatments 600 mg·kg^-1,900 mg·kg^-1 below the rest of the treatment in the most, which be helpful for condensation and institutionalized.(2) Judging from the activity of polyphenol oxidase, the windrow which content Zn of 600 mg·kg^-1 is the highest, is 11.69 mg moshizisu·g^-1·h^-1, 14.94% higher than CK, 12.84% higher than 300 mg·kg^-1, 14.05% higher than 900 mg·kg^-1, 8.70% higher than 1200 mg·kg^-1, is beneficial to the degradation of xylogen and the conversion of its product, have activate effect to the activity of polyphenol oxidase.(3) Judging from the activity of dehydrogenase ,the windrow which content Zn of 600 mg·kg^-1 is the highest, is 14.69 TFug/g·h, 9.92% higher than CK, 14.50% higher than 300 mg·kg^-1, 19.17% higher than 900 mg·kg^-1, 32.41% higher than 1200 mg·kg^-1, is beneficial to the thrive of microorganism and the redox of windrow. Concentration heavy metals Zn treatments 300 mg·kg^-1,600 mg·kg^-1,900 mg·kg^-1 exhibited certain instability in the whole composting process, may be heavy metals Zn having inhibitory effect on dehydrogenase activity meanwhile occurred resistive enzyme activity phenmoenon.3. Effects of heavy metals Zn on microbial community during pig manure composting(1) In composting process, the windrow which content Zn of different concentration, Microbial activities of 600 mg·kg^-1 and 900 mg·kg^-1 concentration treatments were higher, that would be beneficial to increase communities richness and functional diversity. The microorganism in windrow which content Zn of low concentration can use polymers and carbohydrates better, but less of polymers and carbohydrates.(2) The microorganism use the carbon sources in the windrow which content Zn of different concentration , Correlation analysis showed that there was insignificant difference,but significant difference between the concentration treatments of 600 mg·kg^-1 and 900 mg·kg^-1 and the concentration treatments of 300 mg·kg^-1 and 1200 mg·kg^-1, respectively, therefore inferred that the critical value of heavy metals Zn benefited to pig manure composting was between 600 mg·kg^-1 and 900 mg·kg^-1.