Separation, Identification And Research Of Laccase's Activity Of Degrading Phenol Predominant Bacteriain Coking Wastewater

Study on the biodegradation of phenol in the coking wastewater in order to cultivate predominant bacteria as the main object,to separate screening,molecular identification,and aim at laccase's characteristics to cultivate a particular predominant bacteria.Research the bacteria strains by the amount of laccase produced in the appropriate conditions,through biofilm in-depth study on bio-strains degradation.Expermental results are as follows:1.The experimental bacteria was came from China Coal Longhua Harbin Coal Chemical Industry Co., Ltd.actibated sludge in the wastewater treatment system.Put bacteria supernatant of activated sludge into 200mg/L phenol solution,oscillation cultivate with constant temperature,plus phenol concentration 200mg/L each time to 1000mg/L,smear flat to obtain a single strain.After molecular identification,the result was Stenotrophomonas maltophilia K279.2.Observe bacterial colony's characteristics by solid culture,and Bacteria with pure culture for three days and observed on glass slide by AFM(Atomic Force Microscopy),measurement a single bacteria with Nanoscope 5.30r3sr3,the results show that S. maltophilia K279 length 66.591nm,width 59.963nm,without flagella,non-capsular,bacillus brevis.24-hour growth curve shows the whole trend rise, and 16.hours later into a stable growth stage.3.Determinate the impact of laccase activity under the phenol concentration, temperature, and pH. Experimental results show that:When the temperature at 35℃～40℃, pH at 6.5～7.5, the strains have good growth state, the enzyme activity is higher.4.Measuring laccase activity at 4h,8h,16h,20h,24h.The lowest laccase activity at 8h,the laccase activity followed by an increase time to rise, when in 24h its reached the peak value.5.Using ceramisite,activated charcoal,pholyethylene(PE) to culture biofilm,and scanning by an electron microscope after pretreatment.Observed:analysed in a fixed bacteria number,distribution and growth status, three kinds of fillers can be used as S. maltophilia K279 carrier materials, and ceramisite and PE is better.6.Microbial immobilization can maintain a high cell density,thereby enhancing its laccase capacity,under three different experimental conditions determinate biofilm bacteria.The results showed that laccase activity with PE immobilized have low temperature sensitibity,while the optimum temperature is between 35℃～45℃, and 6.5～7.5 pH the growth of S. maltophilia K279 was the best;when the phenol concentration was higher than 600mg/L,the strains for its adaptation are stronger,the laccase activity is higher. When the phenol concentration of 800mg /L,predominant bacteria can adapt the high phenol environment after 8 hours and produce a large number laccase. Also shows that PE is the most suitable carrier for S. maltophilia K279. 7.Put immobilized S. maltophilia K279 into the phenol concentration of 800mg/L culture medium,after 56 hours the degradation rate reached 97.73%,the phenol concentration degraded to 18.13mg/L.It showed that the bacteria be immobilized for the concentration of phenol have a high rate of degradation,do a very good example for phenol degradation in industrial.