Degradation Metabolism And Application Studies Of Bisphenol S By White-Rot Fungi

Bisphenol A(BPA),is one of the most industrially used bisphenol compounds(BPs),due to its potential biological toxicity,it has been regulated and restricted in production and application in many countries and international organizations.Thus,bisphenol S(BPS)has been used extensively as a substitute for BPA in recent years.However,some studies reports that BPS had a similar endocrine-disrupting effect to BPA.BPS has widely detected in various environmental media,posing a potential threat to the ecological environment and human health.Therefore,its environmental residue problem needs to be addressed.Bioremediation is an important method for removing toxic and hazardous environmental pollutants.White-rot fungi are of great interest because of their specific degrading enzymes to degrade a wide range of organic pollutants.However,the degradation characteristics and mechanism of BPS by whiterot fungi are still unclear.In this study,we used the white-rot fungus Phlebia acerina S20190614-6 to investigate the degradation performance and degradation mechanism of BPS under ligninolytic and nonligninolytic conditions.In addition,the feasibility of applying the white-rot fungus P.acerina S20190614-6 to the remediation of bisphenols contaminated wastewater was investigated.The main findings of this paper are as follows:(1)Under the both ligninolytic and non-ligninolytic conditions,the degradation of BPS by white-rot fungus P.acerina S20190614-6 were 96.2% and 99.6% after 7 d of incubation,respectively.The degradation of BPS by P.acerina S20190614-6 was affected by p H and temperature.Under the ligninolytic conditions,the optimum p H was 4.5～5.5 and the optimum temperature was 30 ℃.Under the non-ligninolytic conditions,the optimum p H was 4～6 and the optimum temperature was 30 ℃.(2)The results of cytochrome P450 and enzyme activity experiments indicate that cytochrome P450 may be involved in the degradation of BPS by P.acerina S20190614-6.Under the ligninolytic conditions,Lac played an important role in BPS degradation.Under the non-ligninolytic conditions,Li P played a dominant role.Under the ligninolytic conditions,the chemical structure of the degradation product was identified during the degradation of BPS by P.acerina S20190614-6,the degradation pathway of BPS was postulated to be hydroxylation followed by methylation to form 4-((4-hydroxyphenyl)sulfonyl)-2-methoxyphenol.Based on the results of transcriptome analysis and q PCR,Lac,Li P,Mn P and cytochrome P450 were involved in the degradation of BPS by P.acerina S20190614-6 under the ligninolytic conditions.(3)The white-rot fungus P.acerina S20190614-6 has good remediation effect on simulated BPS and BPs wastewater.Under the static culture,the degradation rates of BPS were 27.6%and 97.9% after 7 d of incubation in unsterilized and sterilized Pearl River water,respectively.Under the shaking culture,when the Pearl River water was sterilized,the removal rate of BPS reached 93.5% after 7 d of incubation for BPS alone.Under the static culture,the degradation rates of bisphenol F(BPF),BPA and BPS were 96.5%,99.9% and 15.9%,respectively,after 7d of incubation when the Pearl River water was not sterilized for simulated wastewater containing multiple BPs.When the Pearl River water was sterilized,BPF and BPA were completely degraded within 4 d,and the degradation rate of BPS reached 93.7% after 7 d.Under the shaking culture,BPF and BPA were 100% removed within 2 d and BPS was completely removed within 7 d when the Pearl River water was sterilized.When the Pearl River water was not sterilized,the removal rates of BPF and BPA were 55.4% and 48.6% respectively after 7 d of shaking incubation,while there was almost no removal of BPS.The removal rate of BPS was increased 124 times after the addition of doubled P.acerina S20190614-6 to unsterilized Pearl River water.