Abstract
Abstract Influence of salinity on acidogenic fermentation (AF) specific to the production of biohydrogen (H2), volatile fatty acids (VFA) and biohythane from food waste (FW) was studied by varying salinity concentration [1 g L−1 (S1), 5 g L−1 (S5), 10 g L−1 (S10), 20 g L−1 (S20), 30 g L−1 (S30), 40 g L−1 (S40) and 50 g L−1 (S50)]. Maximum H2 production rate (HPR) of 0.044 L h−1 and cumulative H2 production (CHP) of 1.05 L was achieved at 40 g NaCl L−1 salinity. Hypersaline conditions (>10 g NaCl L−1) suppressed methanogenic activity and resulted in zero methane evolution. Benefits of salinity were also seen on VFA production with accumulation of more butyric acid (C4: 3.04 g L−1) and acetic acid (C2:1.17 g L−1) along with traces of valeric acid (C5:11 mg L−1) with good acidification potential (AP) of 65.38% at 40 g NaCl L−1. Dehydrogenase (DH) enzyme activity was well correlated with H2 production, wherein S40 showed the highest DH activity of 6.77 μg mL−1. Elevated NaCl concentration (50 g L−1) not only suppressed methanogenic activity but also reduced the acidogenic activity. Increased salinity conditions (30–40 g L−1) depicted good in situ buffering capacity during acidogenic fermentation and also aided in higher H2/VFA production. Study illustrated the significance of salinity as a regulator parameter in aiding the bio-conversion of waste to bioenergy and platform chemicals.
Published Version
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