Ethanol fermentation of tapioca wastewater in anaerobic baffled reactor: Performance evaluation and microbial community analysis

Kharisrama Trihatmoko; Takahiro Watari; Thu Huong Nguyen; Yuga Hirakata; Masashi Hatamoto; Made Tri Ari Penia Kresnowati; Tjandra Setiadi; Takashi Yamaguchi

doi:10.1016/j.biortech.2025.132112

Ethanol fermentation of tapioca wastewater in anaerobic baffled reactor: Performance evaluation and microbial community analysis

Bioresour Technol. 2025 Jan 25:132112. doi: 10.1016/j.biortech.2025.132112. Online ahead of print.

Authors

Kharisrama Trihatmoko¹, Takahiro Watari², Thu Huong Nguyen³, Yuga Hirakata⁴, Masashi Hatamoto⁵, Made Tri Ari Penia Kresnowati⁶, Tjandra Setiadi⁴, Takashi Yamaguchi⁷

Affiliations

¹ Department of Science of Technology Innovation, Nagaoka University of Technology, Niigata 940-2188, Japan.
² Department of Civil and Environmental Engineering, Nagaoka University of Technology, Niigata 940-2188, Japan. Electronic address: watari@vos.nagaokaut.ac.jp.
³ Graduate School of Engineering, Kyoto University, Kyoto 615-8540, Japan.
⁴ Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8560, Japan.
⁵ Department of Civil and Environmental Engineering, Nagaoka University of Technology, Niigata 940-2188, Japan.
⁶ Department of Chemical Engineering, Faculty of Industrial Technology, Bandung Institute of Technology, Bandung 40132, Indonesia; Department of Food Engineering, Faculty of Industrial Technology, Bandung Institute of Technology, Bandung 40132, Indonesia.
⁷ Department of Science of Technology Innovation, Nagaoka University of Technology, Niigata 940-2188, Japan; Department of Civil and Environmental Engineering, Nagaoka University of Technology, Niigata 940-2188, Japan.

PMID: 39870141
DOI: 10.1016/j.biortech.2025.132112

Abstract

Anaerobic treatment of tapioca wastewater has a long processing time. This study aims to evaluate ethanol fermentation as an effective treatment of tapioca wastewater. Simulated tapioca wastewater with an average chemical oxygen demand (COD) of 6900 mg L^-1 was treated in a four-column anaerobic baffled reactor for 300 d. Ethanol production was achieved, however it was inconsistent. Ethanol cycles lasted 10-15 d, with a maximum yield of 51.0 ± 2.2 mg COD L^-1. With each decline in ethanol production, glycerol formation increased, peaking at 10.3 ± 1.7 mg COD L^-1. COD removal efficiency reached 93 %, resulted from biomass formation and sedimentation. Microbial analysis revealed that, during ethanol production, Clostridium sensu stricto 11 and Ethanoligenens were the predominant bacteria, whereas Sordariomycetes, Debaryomycetaceae, and Pichia dominated the fungal community. Meanwhile, Helotiales was prevalent during glycerol formation. Understanding the dynamics of microbial shifts could be key to optimizing ethanol fermentation in future processes.

Keywords: Ethanol production; Glycerol formation; Helotiales; Microbial dynamics; Residual starch content.