Screening Of Inoculums Producing Hydrogen From Citrus Peel

At present, the energy and environmental issues are receiving more and more attention. Hydrogen attracts concern for its clean, high-efficient regarding this globals energy issue. It not only can alleviate the energy crisis, but also can solve the environmental pollution caused by fossil fuels; hence, it has broad application prospects. Fermentative hydrogen production refers to the metabolism of the microorganisms when converting biomass energy into hydrogen. It is pronounced as a potential resolution of energy if hydrogen could be produced through fermenting the solid waste.In this study, firstly, by comparing the H2production potential of microfloa came from different sources of sludge, we got the preferable one(s), followed with the hydrogen production experiment with the glucose and the pretreated citrus peel, to examine the optimal substrate consistency of the microflora(s). Orthogonal test was then carried out to optimize the initial pH, inoculum size, and carbon to nitrogen weight ratio (C/N) of the hydrogen fermentation. The3#inoculum under the best hydrogen production fermentation condition, which is8g’L"1(glucose) or25g’L-1(citrus peel), inoculum size50ml, C/N15:1, reached its highest hydrogen content and hydrogen production,14.11%,36.1mL(glucose); or9.41%、13.9mL(citrus peel). The6#inoculum under the best hydrogen production fermentation conditions, that is20g’L-1glucose inoculum size40ml, C/N15:1, reached its highest hydrogen content11.25%, and hydrogen production,23.0mL respectively; or that is ISOg’L-1citrus peel, inoculum size50ml, C/N15:1, reached its highest hydrogen content and hydrogen production (9.38%、11.8mL, respectively). Through the orthogonal test it was discovered that terminal pH was significantly negatively correlated with hydrogen production, while OD600was significantly directly related with hydrogen production. By compairing the results of experiments, it was also shown that the hydrogen production under the glucose substrate was higher than that under the citrus peel substrate, due to the complexity of the citrus peel. To find the diversity of bacterial communities during H2production, PCR-DGGE was applied to the samples from the start-up phase, stable phase and end stage of fermentation. The community structure changed more in the3#microflora than in the6#microflora, and3#inoculum’s Shannon diversity indexes were higher than the6#inoculum’s. In addition, it is the dominating status of the functional species, instead of the varieties, in the inoculums that determines H2production...