Microbial Community Structures Differentiated in a Single-Chamber Air-Cathode Microbial Fuel Cell Fueled with Rice Straw Hydrolysate

Abstract

Background: The microbial fuel cell represents a novel technology to simultaneously generate electric power and treat wastewater. Both pure organic matter and real wastewater can be used as fuel to generate electric power and the substrate type can influence the microbial community structure. In the present study, rice straw, an important feedstock source in the world, was used as fuel after pretreatment with diluted acid method for a microbial fuel cell to obtain electric power. Moreover, the microbial community structures of anodic and cathodic biofilm and planktonic culturewere analyzed and compared to reveal the effect of niche on microbial community structure. Results: The microbial fuel cell produced a maximum power density of 137.6 ± 15.5 mW/m 2 at a COD concentration of 400 mg/L, which was further increased to 293.33 ± 7.89 mW/m 2 through adjusting the electrolyte conductivity from 5.6 mS/cm to 17 mS/cm. Microbial community analysis showed reduction of the microbial diversities of the anodic biofilm and planktonic culture, whereas diversity of the cathodic biofilm was increased. Planktonic microbial communities were clustered closer to the anodic microbial communities compared to the cathodic biofilm. The differentiation in microbial community structure of the samples was caused by minor portion of the genus. The three samples shared the same predominant phylum of Proteobacteria. The abundance of exoelectrogenic genus was increased with Desulfobulbus as the shared most abundant genus; while the most abundant exoelectrogenic genus of Clostridium in the inoculum was reduced. Sulfate reducing bacteria accounted for large relative abundance in all the samples, whereas the relative abundance varied in different samples.

Performance and microbial community of carbon nanotube fixed-bed microbial fuel cell continuously fed with hydrothermal liquefied cornstalk biomass

“…Previous study showed that it was possible to generate electricity from hydrolysate of cellulosic biomass, such as steam-exploded cornstalk (Zuo et al, 2006), wheat straw (Zhang et al, 2009) and rice straw (Wang et al, 2014b). All these reports were performed in batch mode focused on either feasibility of electricity generation or the analysis of microbial diversity.…”

“…Distinguished from previous study (Wang et al, 2014a,b;Zhang et al, 2009), Proteobacteria which a number of exoelectrogens belong to, was not dominant on the electrode surface of FBMFC in this study. One possible reason is the different niches with diverse environment existing in MFC fed with lignocellulose hydrolysate (Wang et al, 2014b), including degradation of macromolecules (i.e. cellulose and lignin) and conversion of small molecules (i.e.…”

“…HTL was used for cornstalk. Previous investigations used steam-explosion (Zuo et al, 2006) or acids (Wang et al, 2014b) to treat cornstalk or rice straw, respectively. Distinguished from these studies, HTL was firstly used to treat cornstalk for MFC, although the hydrothermal method was employed for the pretreatment of wheat straw (Zhang et al, 2009).…”

Improved TNT detoxification by starch addition in a nitrogen-fixing Methylophilus-dominant aerobic microbial consortium

“…The products were further purified using the QIAquick PCR purification kit (Qiagen) [22]. In order to reduce the bias from replicates and recover sufficient amount of purified amplicons, PCR products from replicates were combined before purification steps [39]. Pyrosequencing of the amplicons was performed by Macrogen (Seoul, South Korea) using a 454/Roche GS-FLX titanium instrument (Roche, NJ).…”

Low-temperature microbial and direct conversion of lignocellulosic biomass to electricity: Advances and challenges

“…The consortium mainly consisted of Bacteroidetes (40%), Alphaproteobacteria (20%), Bacillus (20%), Deltaproteobacteria (10%), and Gammaproteobacteria (10%), while the suspended consortia were predominately Bacillus (22.2%). The microbial community composition may change after MFC operation depending on niches, sulfate-reducing bacteria accounted for large relative abundance [79].…”