Hydrogen And Electricity Production By Microbial Processing Of Biomass

Huge amounts of energy was stored in waste biomass,such as lignocellulose,sewage sludge and organic waste water.In view of the increasing global energy and environmental problems,green,clean and sustainable biotechnology was an alternative to traditional biomass processing method for converting waste biomass into target products.As clean energy,hydrogen and electricity can be produced by microorganisms fermentation by using biomass as substratet under mild reaction conditions.In present study,waste biomass was converted o hydrogen and bioelectricity by microorganism fermentation,including the following content:(1)Study on anaerobic fermentation of corn stover for hydrogen and dissolved organic compounds production.Corn stover was anaerobically digested with C.xellulolyticum DSM 5812 under pH regulation conditions,large amount of hydrogen and organic compounds were produced during the fermentation process.When the concentration of corn stover was 10 g/L,20 g/L and 30 g/L during the fermentation,the final H2 yield was 571 mL/L,901 mL/L and 1163 mL/L,respectively.The main organic compounds produced during corn stover fermentation were acetate,lactate,a small amount of ethanol,along with 4-hydroxy-3-methyl acetophenone and other aromatic compounds produced by lignin degradation.Acetate was the main organic product in the early stage of fermentation.Lactate was accumulated after the concentration of acetate reached 1.6 g/L.The accumulation of ethanol increased after the lactate accumulated to around 1.6 g/L,while the final concentration of ethanol was lower than 0.4 g/L.(2)Study on electricity and hydrogen production with Shewanella putrefaciens by using corn stover anaerobic digested organic compounds.Shewanella putrefaciens was used to construct the microbial fuel cell(MFC)and the microorganism electrolysis cell with corn stover fermentation broth as substrate.S.putrefaciens can use fermentation broth growth without additional nutritions addition.It was found that S.putrefaciens can degrade the organic compounds,also a variety of aromatic compounds through GC/MS analysis,which 2,3-dihydrobenzofuran,4-Hydroxy-3-methylacetophenone,2,6-two methoxy phenol,2,4-bis(1,1-dimethylethyl)-phenol,4-methyl-2,5-two methoxy benzaldehyde degradation rate were 100%,74.9%,65.8%,85%,and 70.5%,respectively.The respective maximum power density were 16.9 mW/m2,15.7 mW/m2,and 15.1 mW/m2,when the concentration of corn stover were 10 g/L,20 g/L and 30 g/L.On the basis of MFC,a microbial electrolysis cell was built.Per gram organic compounds could produce 11.5-12.9 mL of hydrogen with 0.7 V external voltage addition and Pt catalysis.(3)Study on anaerobic digestion of organic sludge and microbial community analysis with electricity generation microorganism.A well performed MFC was constructed with anaerobic sludge as seed solution.The voltage reached 0.62 V with the external resistance of 1000 ?.The power density reached 1247 mW/m2,the internal resistance was about 143 ?,64%of the COD was removed in MFC.Electricity was the only production under MFC process,without any CH4 or H2 production.While in traditional anaerobic fermentation of anaerobic sludge,CH4 and H2 were produced without electricity output.Under the condition of electricity production with MFC,the separation,storage,and transportation methane was avoided.The changes of bacteria and archaea during MFC were analyzed by high throughput sequencing.There was no obvious change of archaea,while tremendous difference of bacteria was observed.The OTU diversity index of MFC was decreased compared with the original anaerobic sludge,and the main bacteria groups were even significant.The concentration of Klebsiella directly relating to electricity production in MFC increased to 16.73%.Hydrogenophaga was also enriched in the process,which may be a new electricity producing microorganism.In summary,this study proposes a new technology for microbial utilization of waste biomass.It also provides technical methods and theoretical support for the related research of microbial conversion of biomass to electricity and hydrogen production.