Improvement of biohythane production from Chlorella sp. TISTR 8411 biomass by co-digestion with organic wastes in a two-stage fermentation

https://doi.org/10.1016/j.ijhydene.2019.03.026Get rights and content

Highlights

  • Co-digestion Chlorella sp. biomass with organic wastes improved biohythane production.

  • Hydrogen and methane yield of co-digestion was 17–75 and 214–577 mL gVS−1.

  • Co-digestion has C/N ratio of 19–41 and H2/CH4 ratio of 0.06–0.3.

  • Co-digestion improved yield, production, C/N ratio, and kinetics.

Abstract

The suitability of molasses, Napier grass (Pennisetum purpureum), empty fruit bunches (EFB), palm oil mill effluent (POME), and glycerol waste as a co-substrate with Chlorella sp. TISTR 8411 biomass for biohythane production was investigated. Mono-digestion of Chlorella biomass had hydrogen and methane yield of 23–35 and 164–177 mL gVS−1, respectively. Co-digestion of Chlorella biomass with 2–6% TS of organic wastes was optimized for biohythane production with hydrogen and methane yield of 17–75 and 214–577 mL gVS−1, respectively. The hydrogen and methane yield from co-digestion of Chlorella biomass with molasses, POME, and glycerol waste was increased by 8–100% and 80–264%, respectively. The biohythane production of co-digestion of Chlorella was 6–11 L L-mixed waste−1 with an optimal C/N ratio range of 19–41 and H2/CH4 ratio range of 0.06–0.3. Co-digestion of Chlorella biomass was significantly improved biohythane production in term of yield, production rate, and kinetics.

Introduction

Microalgal biomass as an alternative feedstock for biofuel production has more attention due to their high organic content, high photosynthetic efficiency, and high CO2 reduction from the environment [1]. However, the commercial microalgae-based biofuels production is not economically viable yet due to the characteristics of the strong cell wall. Microalgal biomass is high protein content as well as an inappropriate C/N ratio resulting in toxic ammonia releasing under anaerobic digestion process [2]. The low biodegradability of microalgal biomass under anaerobic digestion process is depending on the biochemical composition, the nature of the cell wall, and high protein contents [3]. The C/N ratio of microalgal biomass is generally lower than 10, which may cause ammonium inhibition in the anaerobic digestion process [4]. The ammonia can inhibit methanogenic archaea resulting in high volatile fatty acids (VFAs) accumulation in the digester [5]. The ammonia inhibition from high protein content in the microalgal biomass could be reduced through anaerobic co-digestion with a high carbon content substrate. Anaerobic co-digestion with suitable organic waste is a less energy demanding method for improving the anaerobic digestion performance [6]. Anaerobic co-digestion of a homogenous mixture of different organic wastes are also improving the biogas yield [7]. The main benefits of the anaerobic co-digestion process are dilute of toxic compounds in the main substrate, increase the load of biodegradable organic matter, improve the balance of nutrients, enhance microbial diversity, and improve biogas yield [8].

Soybean oil and glycerin were used as a co-substrate for anaerobic digestion of microalgal biomass harvested from wastewater treatment ponds with improving digestion efficiency and biogas yield [9]. Mata-Alvarez et al. [8] reported that the anaerobic digestion of solid waste with organic wastes could establish positive synergism and improved nutrients balance supporting the microbial growth. The anaerobic co-digestion of algal sludge with paper waste increased the methane production (1170 mL L−1) of 2 times compared with algal sludge alone (573 mL L−1) [10]. Zhen et al. [11] also found that anaerobic co-digestion of microalgal biomass with food waste could increase 4.9-fold of methane yield (639 mL CH4 gVS−1) comparing with microalgal alone (106 mL CH4 gVS−1). The anaerobic co-digestion of algal biomass with corn straw increased 62% of methane yield (325 mL CH4 gVS−1) when comparing with algal biomass alone (201 mL CH4 gVS−1) [12]. The anaerobic co-digestion of microalgal biomass with high available organic wastes in an Asian country such as empty fruit bunch (EFB), palm oil mill effluent (POME), molasses, Napier grass, and glycerol waste was not investigated. The EFB, POME, molasses, Napier grass, and glycerol waste are high carbon content and rich in macro-nutrients. The purpose of this work was to assess the possibility of biohythane production from Chlorella sp. TISTR 8411 biomass by co-digestion with organic wastes such as empty fruit bunch (EFB), palm oil mill effluent (POME), molasses, Napier grass, and glycerol waste via two-stage anaerobic digestion under thermophilic condition.

Section snippets

Chlorella sp. TISTR 8411 cultivation and harvesting

Chlorella sp. TISTR 8411 was obtained from the Thailand Institute of Scientific and Technological Research (TISTR), Pathumthani province, Thailand. The strain was cultivated in the BG-11 medium. This medium was composed of (per L of distilled water) 0.4 g NH4Cl, 75 mg MgSO4 *7H2O, 25 mg CaCl2 *2H2O, 11.42 mg H3BO, 4.98 mg FeSO4 * 7H2O, 50 mg EDTA, 31 mg KOH, 0.17 g KH2PO4, 75 mg K2HPO4, 25 mg NaCl, 2.42 g Tris (diluted together with 10 mL diluted acetic acid (1:20)), and 2 mL L−1 of a trace

Conclusions

Co-digestion of Chlorella biomass with organic wastes was significantly improved the biohythane production in term of yield, C/N ratio, gas production, and kinetics. The hydrogen and methane yield from co-digestion of Chlorella biomass with molasses, POME, and glycerol waste was increased by 8–100% and 80–264%, respectively when comparing with digestion Chlorella biomass alone. Co-digestion of Chlorella biomass with 2–6% TS of organic wastes was optimized for biohythane production with hydrogen

Acknowledgments

This work was supported by the National Research Council of Thailand (NRCT) (Grant No. กบง./2558-10), Research and Development Institute of Thaksin University (Grant No. 04–5/2559) and Thailand Research Fund (TRF) through Senior Research Scholar (Grant No. RTA5980004) and Mid-Career Research Grant (Grant No. RSA6180048).

References (44)

  • S. O-Thong et al.

    Evaluation of methods for preparing hydrogen- producing seed inocula under thermophilic condition by process performance and microbial community analysis

    Bioresour Technol

    (2009)
  • A. Giordano et al.

    Monitoring the biochemical hydrogen and methane potential of the two-stage dark fermentative process

    Bioresour Technol

    (2011)
  • S. O-Thong et al.

    Biohydrogen production from cassava starch processing wastewater by thermophilic mixed cultures

    Int J Hydrogen Energy

    (2011)
  • G. Zhen et al.

    Anaerobic co-digestion on improving methane production from mixed microalgae (Scenedesmus sp., Chlorella sp.) and food waste: kinetic modeling and synergistic impact evaluation

    Chem Eng J

    (2016)
  • Y.J. Lee et al.

    Effect of iron concentration on hydrogen fermentation

    Bioresour Technol

    (2001)
  • Claude E. Boyd

    General relationship between water quality and aquaculture performance in ponds

    J Fish Dis

    (2017)
  • R. Li et al.

    Co-digestion of chicken manure and microalgae Chlorella 1067 grown in the recycled digestate: nutrients reuse and biogas enhancement

    Waste Manag

    (2017)
  • M. Wang et al.

    Anaerobic co-digestion of microalgae Chlorella sp. and waste activated sludge

    Bioresour Technol

    (2013)
  • J.H. Mussgnug et al.

    Microalgae as substrates for fermentative biogas production in a combined biorefinery concept

    J Biotechnol

    (2010)
  • X. Wang et al.

    Optimizing feeding composition and carbon-nitrogen ratios for improved methane yield during anaerobic co-digestion of dairy, chicken manure and wheat straw

    Bioresour Technol

    (2012)
  • S. Xie et al.

    Effect of pig manure to grass silage ratio on methane production in batch anaerobic co-digestion of concentrated pig manure and grass silage

    Bioresour Technol

    (2011)
  • S. Astals et al.

    Identification of synergistic impacts during anaerobic co-digestion of organic wastes

    Bioresour Technol

    (2014)
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