Improving production of volatile fatty acids and hydrogen from microalgae and rice residue: effects of physiochemical characteristics and mix ratios
Sun, Chihe; Xia, Ao; Liao, Qiang; Fu, Qian; Huang, Yun; Zhu, Xun; Wei, Pengfei; Lin, Richen; Murphy, Jerry D.
Date:
2018-09-11
Copyright:
© 2018 Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license
Full text restriction information:
Access to this article is restricted until 24 months after publication by request of the publisher.
Restriction lift date:
2020-09-11
Citation:
Sun, C., Xia, A., Liao, Q., Fu, Q., Huang, Y., Zhu, X., Wei, P., Lin, R. and Murphy, J. D. (2018) 'Improving production of volatile fatty acids and hydrogen from microalgae and rice residue: Effects of physicochemical characteristics and mix ratios', Applied Energy, 230, pp. 1082-1092. doi: 10.1016/j.apenergy.2018.09.066
Abstract:
Dark fermentation may be hindered by insufficient bioavailable carbon and nitrogen sources as well as recalcitrant cell wall structures of substrates. Protein-rich microalgae and carbohydrate-rich rice residue with various mix ratios can optimise biohydrogen and volatile fatty acids production. Optimal pretreatment of the microalgae with 1% H2SO4 and the rice residue with 0.5% H2SO4 under hydrothermal heating (140 °C, 10 min) achieved reducing sugar yields of 187.3 mg/g volatile solids (VS) (hydrolysis efficiency: 54%) and 924.9 mg/g VS (hydrolysis efficiency: 100%), respectively. Multiscale physiochemical characterisations of solid hydrolytic residues confirmed considerable damage to both substrates. Co-fermentation of pretreated rice residue and microalgae at a mix ratio of 5:1 exhibited the maximum hydrogen yield of 201.8 mL/g VS, a 10.7-fold increase compared to mono-fermentation of pretreated microalgae. The mix ratio of 25:1 resulted in the highest carbon to volatile fatty acids conversion (96.8%), corresponding to a maximum energy conversion efficiency of 90.8%.
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