Study On The Isolation Of Phenol Degrading Bacteria And Their Degradation Performance

Phenol pollution is a serious threat to human health and ecological environment.Biological method is more and more used to degrade aromatic compounds because of its economic and efficient advantages.However,at present,most microorganisms that degrade aromatic substances can only tolerate low concentrations of aromatic substances and have strong specificity.In order to obtain bacteria that can degrade a variety of aromatic compounds and tolerate high concentrations of phenol,we obtained two high-efficiency degrading bacteria JHB5 and A19 from contaminated sludge.We are identified and domesticated the two degrading bacteria,analyzed the degradation performance,broad spectrum of substrate,ammonia production capacity and nitrogen fixation capacity,and studied the adsorption and degradation of phenol by biochar cooperative strain A19.The results were as follows:Strains A19 and JHB5 can degrade benzene,anthrone,phenol,naphthalene,aniline,oxazole and other aromatic substances,and can degrade acetochlor and pentachloronitrobenzene.They can also produce ammonia and nitrogen fixation,provide nitrogen source for plants and promote plant growth.Based on physiological and biochemical identification and 16S rDNA sequence analysis,the two strains were identified Bacillus sp..However,the ability of Bacillus sp.A19 to degrade aromatic substances is better than Bacillus sp.JHB5.Bacillus sp.A19 has high efficiency in degrading phenol.Bacillus sp.A19 can completely degrade 1000mg/L phenol within 22 hours,and the degradation time is about 55%shorter than that of most strains（48h）.Bacillus sp.A19 has strong environmental tolerance.Bacillus sp.A19 has a wide tolerance range to temperature.In the temperature range of 15-37℃,the degradation rate of phenol by Bacillus sp.A19 can reach 100%.Secondly,Bacillus sp.A19 has good tolerance to a variety of high concentrations of heavy metal ions.In 100mg/L Zn²⁺and Cu²⁺solution,Bacillus sp.A19can remove more than 80%of phenol in phenol solution（1000mg/L）within 20h.The phenol containing Wastewater Degraded by Bacillus sp.A19 is environmentally friendly.The results showed that the growth status of mung bean,corn,rice,melon,Leymus chinensis and quinoa irrigated with degraded phenol containing wastewater was no different from that irrigated with clean water.Adding biochar into the reaction system can improve the rate of microbial degradation of phenol.After adding biochar,the degradation time of phenol（1000mg/L）by Bacillus sp.A19was shortened by 1/3.Under the influence of different initial phenol concentration,temperature,pH,salt concentration and heavy metals,the phenol removal effect of biochar combined with Bacillus sp.A19 is better than that of a single strain.The degradation performance of Bacillus sp.JHB5 was improved in domestication culture.Through four times of domestication,the degradation ability of the strain was increased by about 40%.With the increase of phenol concentration,the growth of Bacillus sp.JHB5 was inhibited,the degradation time was prolonged,and the reaction rate became slower.However,the strain has high phenol degradation efficiency.It can completely degrade 1000mg/L phenol in29h.The degradation time of JHB5 is about 40%shorter than that of most strains（48h）.