| The environmentally harmful antibiotics and heavy metals are largely remained in, theymay lead to a set of problems if lacking of efficient process urines and dung. Composting is abiological process that aerobic microorganism converts organic materials such as agriculturewastes to a more stable ones similar to humus, making it a suitable way of recycling organicwastes in an environmentally friendly manner. This study was aimed to access the effects ofheavy metal and antibiotics on enzymes activities and microbial community functionaldiversity during composting. Microbial community functional diversity was determined byBiolog, PCR-DGGE and T-RFLP, respectively. The research results were as follows:1. Effect of Sulfamethoxazole (SMZ) on properties and enzymes activities duringcomposting(1) High concentration (95mg·kg-1) SMZ could significantly inhibit microorganismactivity, resulting in the compost temperature was difficult to meet the national standards.However, it could activate the activity of polyphenol oxidase as well as dehydrogenase topromote the condensation of humus and aromatization. The effects of cellulase and ureaseactivity were mainly for activation and presented “inhibition-activation-inhibition”by SMZ.50mg·kg-1of SMZ could have significantly negative impact on cellulose and alkalinephosphatase.5.0mg/kg of SMZ can significantly inhibit urease activity.(2) The treatment of95mg·kg-1SMZ had no significant inhibition on average wellcolor development (AWCD),while it had a significant inhibition on Shannon index andSimpson index as compared to the control (P>0.05). The treatment of50mg·kg-1SMZ had asignificant inhibition on AWCD, while it could significantly decreased utilization of aminesand polyphenols. On the contrast, the treatment of95mg·kg-1SMZ significantly decreasedutilization of Polymers, carbohydrates and amines;Bacterial microbial diversity was determined by DGGE method, during the compostingprocess, all treatments had greater differences with the control. In the heating and coolingphases, the treatment of5mg·kg-1SMZ showed the largest Shannon index, whereas that of95mg·kg-1was the lowest. In the high-temperature phase, the treatment of95mg·kg-1SMZ hadthe highest Shannon index.2. Effect of Sulfadimidine (SM2) and Zn on properties and enzymes activities during compostingThe process of composting can be affected by either single SM2and Zn or thecombination of SM2and Zn. Treatment of1mg·kg-1SM2extended the time to hightemperature, temperature changing rate under the treatment of25mg·kg-1SM2was higherthan control. Treatments with Zn extended composting time, Zn content of1800mg·kg-1andthe combination of stack body temperature were "M" trends. The control and single Znpollution were close to compost maturity in the25thdays, while the other treatments did notreach the maturity stage. The combination as well as a high level of Zn in the wholecomposting process inhibited the activity of alkaline phosphatase, while a high concentrationof SM2improved it. High concentration of Zn showed a role of activation on urease; addingSM2and combined pollution inhibited it. On the6thdays, dehydrogenase activity decreasedwith the increasing concentration of pollutants, but the effect of combination ranged betweenthat of the two individual pollutants. On the25thdays, treatment of600mg·kg-1Znsignificantly increased the dehydrogenase activity, that’s opposite for the combination..3. Effect of Sulfadimidine (SM2) and Zn on functional diversity of microbial communityduring composting(1) The Biolog results showed all the pollutants inhibited the microorganism, especiallyat the level of Zn1800. Shannon index, average well color development (AWCD) andsubstrate utilization decreased significantly with increasing concentration of Zn or thecombination of two pollutants at6thday (P<0.05). At day25th, the combination changed toimprove microbial community function and also increased Shannon’s diversity, AWCD andutilization of substrate as compared to individuals, as well as a positive effect on themicroorganism diversity.(2) Bacterial community diversity determined by DGGE analysis showed that, at6thdaythe highest H value at treatment of25mg·kg-1SM2indicated that it increased the bacterialmicrobial diversity. At25thday, treatment of600mg·kg-1Zn had the largest Shannon indexand improved the microbial diversity; other treatments belowed the the control, reduced thebacterial community diversity.(3) Fungal community diversity was determined by T-RFLP. In the intial composting,Stockpiles fungal community diversity was reduced with addition of pollutants. In the finalcomposting, S1and S1+Zn600can improve the fungal community diversity, Zn1800and S25had great influence on fungal community diversity. |
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