Bioethanol production from Chlorella vulgaris ESP-31 grown in unsterilized swine wastewater

Paula Isabel G Acebu; Mark Daniel G de Luna; Chun-Yen Chen; Ralf Ruffel M Abarca; Jih-Heng Chen; Jo-Shu Chang

doi:10.1016/j.biortech.2022.127086

Bioethanol production from Chlorella vulgaris ESP-31 grown in unsterilized swine wastewater

Bioresour Technol. 2022 May:352:127086. doi: 10.1016/j.biortech.2022.127086. Epub 2022 Mar 29.

Authors

Paula Isabel G Acebu¹, Mark Daniel G de Luna², Chun-Yen Chen³, Ralf Ruffel M Abarca⁴, Jih-Heng Chen⁵, Jo-Shu Chang⁶

Affiliations

¹ Energy Engineering Program, National Graduate School of Engineering, University of the Philippines Diliman, Quezon City 1101, Philippines.
² Energy Engineering Program, National Graduate School of Engineering, University of the Philippines Diliman, Quezon City 1101, Philippines; Department of Chemical Engineering, University of the Philippines Diliman, Quezon City 1101, Philippines.
³ University Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan.
⁴ Department of Chemical Engineering, University of the Philippines Diliman, Quezon City 1101, Philippines.
⁵ Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan.
⁶ Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan; Department of Chemical and Materials Engineering, Tunghai University, Taichung 407, Taiwan; Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 32003, Taiwan. Electronic address: changjs@mail.ncku.edu.tw.

PMID: 35364235
DOI: 10.1016/j.biortech.2022.127086

Abstract

The potential of microalgae to remove nutrients from swine wastewater and accumulate carbohydrates was examined. Chlorella sorokiniana AK-1 and Chlorella vulgaris ESP-31 were grown in 10% unsterilized swine wastewater and obtained a maximum carbohydrate content and productivity of 42.5% and 189 mg L^-1d^-1, respectively. At 25% wastewater and 25% BG-11 concentration, the maximum carbohydrate productivity and total nitrogen removal efficiency of C. vulgaris ESP-31 were improved to 266 mg L^-1d^-1 and 54.2%, respectively. Further modifications in light intensity, inoculum size, and harvesting period enhanced the biomass growth, carbohydrate concentration, and total nitrogen assimilation to 3.6 gL^-1, 1.8 gL^-1, and 92.2%, respectively. Ethanol fermentation of the biomass resulted in bioethanol yield and concentration of 84.2% and 4.2 gL^-1, respectively. Overall, unsterilized swine wastewater was demonstrated as a cost-effective nutrient source for microalgal cultivation which further increases the economic feasibility and environmental compatibility of bioethanol production with concomitant swine wastewater treatment.

Keywords: Bioethanol production; Carbohydrate accumulation; Microalgae; Total nitrogen removal; Wastewater treatment.

MeSH terms

Animals
Biomass
Carbohydrates
Chlorella vulgaris*
Microalgae*
Nitrogen
Swine
Wastewater

Substances

Carbohydrates
Waste Water
Nitrogen