Engineering Shewanella carassii, a newly isolated exoelectrogen from activated sludge, to enhance methyl orange degradation and bioelectricity harvest  

作　　者：Chi Yang Junqi Zhang Baocai Zhang Dingyuan Liu Jichao Jia Feng Li Hao Song 

机构地区：[1]Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education),Tianjin University,Tianjin,300072,China [2]Collaborative Innovation Center of Chemical Science and Engineering(Tianjin),School of Chemical Engineering and Technology,Tianjin University,Tianjin,300072,China [3]Qingdao Institute Ocean Engineering of Tianjin University,Tianjin University,Qingdao,266200,China

出　　处：《Synthetic and Systems Biotechnology》2022年第3期918-927,共10页合成和系统生物技术（英文）

基　　金：supported by the National Key Research and Development Program of China(2018YFA0901300);the National Natural Science Foundation of China(NSFC 32071411,32001034,and 21621004);Tianjin Science and Technology Plan Project(20JCQNJC00830);Tianjin Research Innovation Project for Postgraduate Students(2020YJSB045).

摘　　要：Electroactive microorganisms(EAMs)play important roles in biogeochemical redox processes and have been of great interest in the fields of energy recovery,waste treatment,and environmental remediation.However,the currently identified EAMs are difficult to be widely used in complex and diverse environments,due to the existence of poor electron transfer capability,weak environmental adaptability,and difficulty with engineering modifications,etc.Therefore,rapid and efficient screening of high performance EAMs from environments is an effective strategy to facilitate applications of microbial fuel cells(MFCs).In this study,to achieve efficient degradation of methyl orange(MO)by MFC and electricity harvest,a more efficient exoelectrogen Shewanella carassii-D5 that belongs to Shewanella spp.was first isolated from activated sludge by WO_(3) nanocluster probe technique.Physiological properties experiments confirmed that S.carassii-D5 is a Gram-negative strain with rounded colonies and smooth,slightly reddish surface,which could survive in media containing lactate at 30℃.Moreover,we found that S.carassii-D5 exhibited remarkable MO degradation ability,which could degrade 66%of MO within 72 h,1.7 times higher than that of Shewanella oneidensis MR-1.Electrochemical measurements showed that MFCs inoculated with S.carassii-D5 could generate a maximum power density of 704.6 mW/m^(2),which was 5.6 times higher than that of S.oneidensis MR-1.Further investigation of the extracellular electron transfer(EET)mechanism found that S.carassii-D5 strain had high level of c-type cytochromes and strong biofilm formation ability compared with S.oneidensis MR-1,thus facilitating direct EET.Therefore,to enhance indirect electron transfer and MO degradation capacity,a synthetic gene cluster ribADEHC encoding riboflavin synthesis pathway from Bacillus subtilis was heterologously expressed in S.carassii-D5,increasing riboflavin yield from 1.9 to 9.0 mg/g DCW with 1286.3 mW/m^(2) power density output in lactate fed-MFCs.Furthermore,results show

关 键 词：Microbial fuel cells WO_(3)nanocluster probe Shewanella carassii RIBOFLAVIN Methyl orange 

分 类 号：X705[环境科学与工程—环境工程]