Nano zero valent iron embedded on chitosan for enhancement of biohydrogen production in dark fermentation

Chitosan supported nano zero valent iron (nZVI/CS) was used as a catalyst to improve biohydrogen production. Dark fermentation was carried out by Enterobacter aerogenes using glucose as a carbon source under mesophilic condition at 37 degrees C. TEM analysis confirmed the morphological arrangement of nano sized zero valent iron embedded on chitosan. The highest biohydrogen yield was 243 mLH(2)/g(glucose) which was 30% higher than the control. The corresponding initial pH was 6.8 and optimum nZVI/CS concentration was identified as 150 mg/L. Volatile fatty acids (VFA) distribution indicated the acetic pathway was undertaken to produce biohydrogen resulting in a positive correlation between hydrogen yield and acetic acid concentration. The presence of propionic acid and ethanol has negatively affected the hydrogen yield. (C) 2020 TheAuthors. Published by Elsevier Ltd.