Self-sustained ammonium recovery from wastewater and upcycling for hydrogen-oxidizing bacteria-based power-to-protein conversion

Xiaoyong Yang,Yufeng Jiang,Song Wang,Rusen Zou,Yanyan Su,Irini Angelidaki,Yifeng Zhang

doi:10.1016/j.biortech.2021.126271

Xiaoyong Yang, Yufeng Jiang + Show 5 more

Open Access

https://doi.org/10.1016/j.biortech.2021.126271

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Journal: Bioresource Technology	Publication Date: Nov 5, 2021
Citations: 13	License type: cc-by

Affiliation: Technical University of Denmark

Abstract

Microbial protein (MP) production by autotrophic hydrogen-oxidizing bacteria is regarded as a potentially sustainable approach to mitigate food crisis, water pollution, and climate change. Herein, a hybrid biological-inorganic (HBI) system which coupled energy-neutral ammonium recovery and in-situ upcycling for MP production was demonstrated. No energy and acids/bases were needed for ammonium recovery and pH control. The system was tested with different amounts of CO2 supply and operated at different operational modes (microbial fuel cell or microbial electrolysis cell mode). 0.381 g/L of biomass containing 64.79% of crude protein was produced using the recovered nitrogen and therefore led to 76.8% of ammonium recovery and 84.6% of COD removal from real municipal wastewater. The system although not yet optimal in terms of efficiency has a meaning in alleviating food crisis and environmental issues. Altogether, this study offers insight into developing an energy and resource-efficient power-to-protein process to supplement conventional food production globally.

Highlights

Anthropogenic activities have significantly changed the planet and resulted in many environmental issues in recent centuries, such as global climate change, biodiversity loss, water and land pollution, and food and energy crises
The system was tested with different amounts of CO2 supply and operated at different operational modes. 0.381 g/L of biomass containing 64.79% of crude protein was produced using the recovered nitrogen and led to 76.8% of ammonium recovery and 84.6% of Chemical oxygen demand (COD) removal from real municipal wastewater
Microbial protein (MP) production by hydrogen-oxidizing bacteria (HOB) can be driven by electricity and is regarded as an essential part of the circular economy since it could close the loop of carbon and nitrogen

Summary

Introduction

Anthropogenic activities have significantly changed the planet and resulted in many environmental issues in recent centuries, such as global climate change, biodiversity loss, water and land pollution, and food and energy crises. A sustainable and circular bioeconomy that can recycle nutrients and carbon for food production is eagerly needed to address these challenges (Stahel, 2016). Microbial protein (MP), or single cell protein (SCP), the protein-rich biomass and a sustainable substitution of traditional plant/animal-based protein (Matassa et al., 2016), is expected to be one of the potential solutions to feed the increasing population on the earth. To feed the HOB, H2 and O2 can be generated through water splitting using renewable electric power; CO2 can be derived from industrial off-gas or raw biogas; and the nitrogen can be recovered from wastewater (Mishra et al, 2020). MP production by HOB can be driven by electricity (namely Power-to-Protein) and is regarded as an essential part of the circular economy since it could close the loop of carbon and nitrogen

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