Strain screening and optimization of biohydrogen production by Enterobacter aerogenes EB-06 from glycerol fermentation

Abstract

Biohydrogen technology has drawn much attention due to its many advantages. However, it is still necessary to screen much more strains with stronger hydrogen-producing capacity for future commercialization processes. In this paper, a biohydrogen-producing strain Enterobacter aerogenes EB-06 was isolated, identified, and named. It could convert glycerol to biohydrogen by microorganism fermentation. The effects of oxygen content, initial pH, initial glycerol concentration, and initial nitrogen source content on biohydrogen production process were investigated. The results have shown that biohydrogen generation was more favorable under anaerobic conditions. The optimum specific biohydrogen production rate (QH2) was obtained as 41.47 mmol H2/g DCW h at 40 g/L initial glycerol concentration. The optimum volume H2 yield (CH2) was 83.76 mmol H2/L at initial pH 7.0. It was found that nitrogen source content (0–4 g/L) could promote biohydrogen production and cell growth. The biohydrogen production of Enterobacter aerogenes EB-06 from glycerol was optimized by the orthogonal experimental design. The optimal yield coefficient of biohydrogen from glycerol fermentation (YH2/glycerol) of EB-06 was obtained as 1.07 mmol H2/ mol glycerol at 10 g/L initial glycerol concentration, initial pH 5.0, and initial C/N ratio 5/3.