Study On System Of Microbial Hydrogen Production

Biomass can be degraded by microbe into sugar which can subsequently be converted into energy source such as hydrogen. Such a process is significant when applied to put off energy source crisis, debate environmental pollution and realize the strategy of sustainable economy.Hydrogen production from rice straw by simultaneous saccharification and fermentation (SSF) was studied using the Klebsiella oxytoca HP1 in this report. The experiments of batch ferment hydrogen production were carried out in 600-mL serum bottles. Single factor and orthogonal experiments showed that the optimal conditions for hydrogen production were: pH6.5, ferment temperature 40℃, cellulose dose 20 FPAU/g rice straw, shake rate 100r/min and ferment time 42 h. The maximum H2 production (110.6 mL/g rice straw) was obtained under the above conditions. The enlarge experiments were carried out in a 10- L bioreactor , a maximum H2 production of 122.3 mL/g rice straw was achieved. The H2 production increased by 34.4% compared with the separated hydrolysis and fermentation hydrogen production. This research indicated a perfect application of SSF in biohydrogen production from cellulose material.Hydrogen production by a mixed culture of R. capsulata CN1 and K. oxytoca HP1 was investigated. The experiments of batch ferment hydrogen production were carried out in 140-mL serum bottles which were filled with argon (Ar). The optimal conditions for hydrogen production were: initial pH 7.5, light intensity 4000lux, Rhodopseudomona capsulata CN 1 inculation volume 20%, 3g/L peptone as nitrogen resource and the sodium glutamate secondary. The stasis stage was evidently shortened when ammoniate were added as nitrogen source, but the yield of H2 production decreased. The anaerobic atmosphere is necessary for hydrogen production,even 3%oxygen can decrease the production of hydrogen. Under the optimal conditions the maximum H2 production was obtained as 4.0 mol H2/ mol (CH20)6 with a H2 yield of 66.7%.The liquid waste of SSF includes lots of organic acids(butyric acid 2.55 g/L, acetic acid 0.51 g/L)and suger (3.1 g/L) which can be used by Rh. capsulate CN1 and K. oxytoca HP1. Under the optimal conditions of mixed culture, the amount of hydrogen produced by the waste liquid of SSF was 920 mL H2/L. The total H2 production was 140.7 mLH2/g rice straw by the process of SSF and mixed culture。The liquid waste from biohyhrogen contains SCP(sinle cell protein) which can be recycled. In this research, chitosan has been used for receiving bacterium from wastewater .The result showed that the FR was 92.1%, and COD 40%, when the conditions were pH 4.5, chitosan dosage 60mg/l and 40℃. Under the optimal conditions the filtration speed of the flocculated sample was improved dramatically. When the chitosan and the flocculant of 130 were used together, the FR can reach 94.1% .