Media Improvement for Hydrogen Production Using C. acetobutylicum NCIMB 13357

Abstract

Problem statement: Some component of fermentation medium showed to reduce the bacterial production of hydrogen. Approach: Reinforced clostridium medium is a selected medium for Clostridium species. Reformulation this medium regarding hydrogen production may focus on such medium composition that enhance or reduce the bacterial productivity. The optimum pH and temperature for hydrogen production were at initial pH of 7.0 and 30ºC. Results: The results show that both nitrogen source and its concentration affected biomass growth as well as H 2 yield. Yeast extract at concentration of 13 gL −1 was the best organic nitrogen source and resulted in hydrogen yield (Y P/S) of 308 mL g −1 glucose utilized with biomass concentration of 1.1 gL −1 , hydrogen yield per biomass (Y P/X) of 280 mL g −1 L −1 , biomass per substrate utilized (Y X/S) of 0.22 and produced hydrogen in gram per gram of glucose utilized (Y H2/S) of 0.0275. C/N of 70 enhanced the Y P/S from 308 mL g −1 to 350 mL g −1 glucose utilized with biomass concentration of 1.22 gL −1 , Y P/X of 287 mL g −1 L −1 , Y X/S of 0.244 and (Y H2/S) of 0.03125. In the absence of sodium chloride and sodium acetate further enhanced Y P/S from 350 mL g −1 glucose utilized to 391 mL g −1 glucose utilized with maximum hydrogen productivity of 77.5 mL L −1 h −1 , whereas RCM medium gave the highest hydrogen productivity of 63.5 mL L −1 h −1. Results also show that Sodium Chloride and Sodium Acetate in the medium adversely affect growth. Removal of both components from the medium enhanced the biomass concentration from 1.22-1.34 gL −1 , Y P/X of 254 mL g −1 L −1 , Y X/S of 0.268 and (Y H2/S) of 0.0349. Conclusion: The medium an improved containing (glucose 5 gL −1 , Yeast extract gL −1 , L-Cystine. HCl 1 gL −1 and Bacteriological agar 0.5 gL −1), was able to enhance the hydrogen productivity.

Optimization of key factors affecting biogas production from synthetic wastewater by anaerobic granular sludge

“…In addition, it is normally found that microorganisms utilize carbon 25–30 times faster than nitrogen. To meet this requirement, a C/N ratio of 20–30:1 is needed . But, the optimum C/N ratio varied depending on types of substrate and microorganism used.…”

“…Ammonia nitrogen is regarded as a potential inhibitor during anaerobic digestion, particularly when dealing with complex type of substrates [14].Thus, a negative correlation exists between biogas yield and NH 1 4 -N. In addition, it is normally found that microorganisms utilize carbon 25-30 times faster than nitrogen. To meet this requirement, a C/N ratio of 20-30:1 is needed [28]. But, the optimum C/N ratio varied depending on types of substrate and microorganism used.…”

Orthogonal optimization of Carboxydothermus hydrogenoformans culture medium for hydrogen production from carbon monoxide by biological water-gas shift reaction

“…The results were analyzed considering the minimization of the Ca þ P content of cells as the optimization criterion (Table 5). From variance analysis (not shown), only the F ratios of Ca, 4.2, was larger than the critical value of F 0.05 (2,18), indicating that only this factor had a significant impact on the mineral content. The magnitude of the variance, expressed in percentage, reflects the significance of the contribution of each factor, hence their ranking, toward this target (Table 6).…”

“…In this study, the minimum MS of the four factors is considered as the experimental error considering that the unbiased estimates of the sum of squares are much smaller than the variance of the other factors. A factor is considered as having an impact which is statistically significant at a probability of 99% and 95% if the F ratio calculated for the factor evaluated is greater than the critical value of the F distribution with 2 and 18 df for a P-value of 0.01 and 0.05, F 0.01 (2,18) and F 0.05 (2,18), i.e. 6 and 3.6, respectively.…”

“…As above, the optimal medium composition was determined from the K values, as following: PO larger than the critical value of F 0.05 (2,18), had also a significant effect although at a lesser degree. The effect of the two major independent variables, Ca 2þ and PO (Table 3), while higher concentration of those cations might repress the H 2 production rate, as shown in Fig.…”