Impact Of Metabolic Regulators On The Biogas Production In Anaerobic Systems

Biogas becomes one of the alternative energy sources for its renewable and non-polluted utilization. In this article, we investigated the impact of regulatory factors on biogas production in anaerobic systems using sludge as inoculums, got a methane-producing strain and studied its biochemical characteristics. The results showed as follows:1) Biogas production in wastewater system was enhanced by 40.2%,47.4%,23%,35.9%,16.1% and 48.8% than that of control with the optimum addition of malate (0.5 g/L), citrate (1.0 g/L), a-ketoglutate (0.2 g/L), oxalate (0.1 g/L), succinate (1.2 g/L) and glutamate (0.3 g/L) containing 0.5 g/L lactate, respectively. Meanwhile, The total solids (TS) was increased by 15.2%,28.2%,11.1%,11.2%,4.4% and 12.5% than control. The biogas yield on volatile fatty acids consumed (YP/V) was improved by 35.4%,47.2%,20.1%,31.6%,7.0% and 43.4% than control, respectively. Biogas production rate (qp) was also increased by 22.4%,19.5%,10.7%,22.3%,10.9%, and 31.7% than that of control, respectively. The results suggested that the ability of strains in anaerobic system to grow and biosynthesize methane was facilitated with regulators.2) Biogas production in wastewater system cultivated only with methanogens was also enhanced by 47.6%,39.7% and 54% than that of control with the optimum addition of malate (0.5 g/L), citrate (1.0 g/L) and glutamate (0.3 g/L) containing 0.5 g/L lactate, respectively.3) The optimum rate of malate (X1), citrate (X2) and glutamate (X3) was 0.52 g/L, 1.06 g/L and 0.33 g/L by using the response surface method in organic wastewater contained 0.05 g/L lactate as a raw material. Meanwhile, The regression equation was follow:Y=435.6667+5.5X1+4.875X2 +7.875X3-24.333333X12+0.25X1X2+1.25X1X3-22.58333X22+2X2X3-19.58333X32. The max biogas theoretical production was 435.67mL. Five parallel tests were done under the optimized parameters, and the average biogas production was 453.82 mL with relative error of 4.16%.4) Methanogen, named by S-1, was isolated from anaerobic sludge with acetate as carbon and energy using Hungate anaerobic technology. The colony in roll tube was white, opaque, relatively circular, smooth and heap-like aggregation. Cells in culture showed as small spherical and appeared blue-green fluorescence in the fluorescent microscope. The optimum growth pH value and growth temperature of S-1 was 7.0 and 37℃, respectively.