Effect of food to microorganism ratio on biohydrogen production from food waste via anaerobic fermentation

Bio-hydrogen production from thin stillage using conventional and acclimatized anaerobic digester sludge

“…The maximum hydrogen production rate in batches using ADS was 18.4 mL/h at S 0 /X 0 ratio of 1 gCOD/ gVSS which is one third the 57.9 mL/h in batches using AADS at S 0 /X 0 ratio of 4 gCOD/gVSS. The trend of an increase to the maximum followed by a decline at higher S 0 /X 0 ratio is consistent with the findings of Jinming et al [11] who observed an increase in the hydrogen production rate with the increase of S 0 /X 0 ratio to a maximum of 19.5 mL/h at an S 0 /X 0 ratio of 5 gVS feed /gVS seed , followed by a decrease with further increase in the S 0 /X 0 ratio. A correlation (not shown) of the biomass specific production rate for ADS and AADS (R 2 of 0.72) revealed that over the range of S 0 /X 0 ratios that was studied, the active biomass (hydrogen producers) in the AADS is 3.5 times than that of the ADS calculated based on the specific hydrogen production rates for both sludges.…”

“…In the ADS batches as the S 0 /X 0 ratio increased from 0.5 to 2 gCOD/gVSS, hydrogen production rapidly increased from 49 mL at S 0 /X 0 ratio of 0.5 gCOD/gVSS to a maximum of 386 mL at S 0 /X 0 ratio of 2 gCOD/gVSS after which it decreased to 163 mL with further increase in S 0 /X 0 ratio. This behavior is consistent with another study [11] that used food waste as a substrate and anerobic digester sludge as the seed, where a wide range of S 0 /X 0 ratios from 1 to 10 gVS feed /gVS seed was studied in mesophilic batch fermentation tests. In the aforementioned study, hydrogen production initially increased at high S 0 /X 0 ratios and reached a maximum of 357 mL at an S 0 /X 0 ratio of 6 gVS feed /gVS seed , then decreased at S 0 /X 0 ratios greater than 6 gVS feed /gVS seed .…”

“…However, considering the 5% standard deviation of hydrogen gas production, it is likely that the optimum S 0 /X 0 range is between 3 and 6 gCOD/gVSS. This trend is similar to that observed by Jinming et al [11] who used food waste as the substrate and anaerobic digester sludge as the seed, where the hydrogen yield increased slowly to a maximum of 39 mL H 2 /gVS at S 0 /X 0 ratio of 6 gVS feed /gVS seed prior to decreasing to almost zero at S 0 /X 0 ratio of 8 gVS feed / gVS seed and higher. In addition, in another study [12], the same trend was observed in batches using seed sludge from a local anaerobic digester and food waste as the substrate, with a maximum yield of 101 mL H 2 /gCOD at S 0 /X 0 ratio of 7.68 gCOD/gVSS.…”

“…There is strong evidence that this ratio directly affects the growth patterns of microorganisms [27]. As apparent from Table 1, the extensive work by Pan et al [11] indicated that as the value of S 0 /X 0 ratio increases from 1 to 6 gVS substrate / gVS seed , hydrogen production potential increases then decreases beyond an S 0 /X 0 ratio of 6. The impact of microbial cultures on biohydrogen production from soluble substrates is well documented in the literature is evidenced in Table 1.…”

Bio-Hydrogen Production from Pineapple Waste Extract by Anaerobic Mixed Cultures

“…The maximum hydrogen yield (HY) (1.82 mol H 2 /mol glucose) obtained in this study was favorable compared with other results reported in the literature search (Table 6). However, the P s and HY of Saraphirom and Reungsang [26] were 1.26 and 1.21 times than ours, respectively, while the HY of Pan et al [27] was 1.27 times higher than our HY. This is not surprising since the types/sources of inoculums and substrates used to produce hydrogen in their studies were different to those in our study.…”