Surananee Hayeeyunu. Butanol Production from Two-Stage ABE Fermentation of Food Waste.. Master's Degree(Applied Chemistry). Prince of Songkla University, Pattani Campus. Office of Academic Resources. : Prince of Songkla University, Pattani Campus, 2018.
Butanol Production from Two-Stage ABE Fermentation of Food Waste.
Abstract:
In this study, food waste was used as substrate to feasibly investigate simultaneous hydrogen and butyric acid production from dark fermentation by using enriched mixed-cultures in laboratory scale batch reactor and continuous stirred tank reactor (CSTR) under thermophilic conditions (55 °C). The batch experimental results show that satisfied hydrogen production yield of 135.2 mL H2/g-VSadded was achieved by using initial food waste concentration5.8 g-VS/L. Butyric acid with concentration of 34.57 mM is dominant metabolic product, while other metabolic products of lactic acid, acetic acid and propionic acid were found at more than 5 times lower concentrations of 7.62, 5.76 and 2.30 mM, respectively. The CSTR fed with food waste was operated at 4 day HRT, corresponding to organic loading rate (OLR) of 10 g-VS/Lreactor could produce highest hydrogen production yield of 100 mL H2/g-VSadded, gathering with 6.14 g/L butyric acid.
Butyric acid rich solution could be potentially converted to butanol by using Clostridium sp. In the second stage (ABE production), batch experiments under mesophilic conditions (37oC) were set up to investigate the effect on ABE fermentation by using different bacteria strains (Clostridium beijerinckii ATCC 55025 and Clostridium butylicum TISTR 1032), various initial inoculums concentration (5%, 10% and 15% by volume), different ABE fermentation mediums (Tryptone Yeast extract Acetate, TYA medium and Free-N medium),various initial sugar concentration (20-60 g/L), and different butyric acid to glucose (B/G) ratios (0/20. 1/20, 5/20, 10/20 and 15/20 g/L basis). The highest butanol concentration of 7.93 g/L was achieved from batch fermentation at initial 30 g/L sugar, 10% Clostridium beijerinckii ATCC 55025, and supplemented with TYA medium.
The continuous ABE production under temperature 37 oC was studied by using Packed Bed Reactor (PBR) having 2.5- L working volume. Glucose (30 g/L) supplemented with TYA at flow rate of 500 mL/d. Meanwhile, pH in the reactor was maintained in range of 4.0-6.5. The results show that the main products were butyric acid with concentration of 3-5 g/L and butanol was not detected