Substrate degradation, biodiesel production, and microbial community of two electro-fermentation systems on treating oleaginous microalgae Nannochloropsis sp

Yue Shi; Kaiguo Huang; Xinxiang Pan; Guobing Liu; Yuhang Cai; Asad A Zaidi; Kun Zhang

doi:10.1016/j.biortech.2021.124932

Substrate degradation, biodiesel production, and microbial community of two electro-fermentation systems on treating oleaginous microalgae Nannochloropsis sp

Bioresour Technol. 2021 Jun:329:124932. doi: 10.1016/j.biortech.2021.124932. Epub 2021 Mar 6.

Authors

Yue Shi¹, Kaiguo Huang¹, Xinxiang Pan², Guobing Liu¹, Yuhang Cai¹, Asad A Zaidi³, Kun Zhang⁴

Affiliations

¹ College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001, China.
² Maritime College, Guangdong Ocean University, Zhanjiang 524088, Guangdong, China; Marine Engineering College, Dalian Maritime University, Dalian 116026, China.
³ Department of Engineering Sciences, Pakistan Navy Engineering College, National University of Sciences and Technology, Karachi 75350, Pakistan.
⁴ College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001, China. Electronic address: kunzhang@hrbeu.edu.cn.

PMID: 33713901
DOI: 10.1016/j.biortech.2021.124932

Abstract

Electro-fermentation system (EFS) emerges its effectiveness on treating microalgae for biodiesel production, but much is unknown about biodegradation behaviors, biodiesel characteristics, and microbial community. Compared with conventional fermentation system (CFS), microbial electrolysis cell-based EFS (MEC-EFS) and microbial fuel cell-based EFS (MFC-EFS) were investigated for the performance while treating microalgae Nannochloropsis sp. Results indicated that MEC-EFS presented much higher first-order decomposition rate coefficients of carbohydrates and proteins (1.212/d and 0.951/d) than those of CFS (0.615/d and 0.794/d) and MFC-EFS (0.518/d and 0.415/d). Compared with MFC-EFS, MEC-EFS showed better electrochemical performance (2.17 A/m³vs. 0.95 A/m³). Moreover, MEC-EFS reached the highest extracted lipid to biomass ratio (43.3%), followed by MFC-EFS (32.3%) and CFS (27.7%). By strengthened microbial biohydrogenation, MEC-EFS and MFC-EFS had higher saturated fatty acids ratio (78.8% and 70.6%) than that of CFS (56.1%). For MEC-EFS, enriched Ruminococcus and Geobacter in anodic biofilm might contribute to favorable biohydrogenation and electrochemical performance.

Keywords: Biodiesel production; Electro-fermentation; Microbial electrolysis cell; Microbial fuel cell; Nannochloropsis.

MeSH terms

Bioelectric Energy Sources*
Biofuels
Fermentation
Microalgae*
Microbiota*
Stramenopiles*

Substances

Biofuels