Unlocking the genomic potential of aerobes and phototrophs for the production of nutritious and palatable microbial food without arable land or fossil fuels.

Abbas Alloul,Siegfried E Vlaeminck,Daniel Machado,Janne Spanoghe

doi:10.1111/1751-7915.13747

Abbas Alloul, Siegfried E Vlaeminck + Show 2 more

Open Access

https://doi.org/10.1111/1751-7915.13747

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Abstract

The increasing world population and living standards urgently necessitate the transition towards a sustainable food system. One solution is microbial protein, i.e. using microbial biomass as alternative protein source for human nutrition, particularly based on renewable electron and carbon sources that do not require arable land. Upcoming green electrification and carbon capture initiatives enable this, yielding new routes to H2, CO2 and CO2-derived compounds like methane, methanol, formic- and acetic acid. Aerobic hydrogenotrophs, methylotrophs, acetotrophs and microalgae are the usual suspects for nutritious and palatable biomass production on these compounds. Interestingly, these compounds are largely un(der)explored for purple non-sulfur bacteria, even though these microbes may be suitable for growing aerobically and phototrophically on these substrates. Currently, selecting the best strains, metabolisms and cultivation conditions for nutritious and palatable microbial food mainly starts from empirical growth experiments, and mostly does not stretch beyond bulk protein. We propose a more target-driven and efficient approach starting from the genome-embedded potential to tuning towards, for instance, essential amino- and fatty acids, vitamins, taste,... Genome-scale metabolic models combined with flux balance analysis will facilitate this, narrowing down experimental variations and enabling to get the most out of the 'best' combinations of strain and electron and carbon sources.

Highlights

Food production and the planetary boundaries are already beyond the limits of sustainability (Steffen et al, 2015), yet even more pressure on Earth’s carrying capacity is expected with the global population projected to reach 9.2–12.3 billion people by the turn of the century and the rise in living standards (Gerland et al, 2014)
Despite the environmental advantages of microbial protein as a food ingredient, studied and industrial production ways are mostly based on agricultural products or fossil fuels as a source of electron donors and/or carbon sources such as molasses, sucrose, starch, methane from natural gas, n-alkanes and methanol (Nasseri et al, 2011)
Renewable H2 or CO2-derived compounds can be used as an electron donor and/or carbon source for more sustainable microbial protein production (Pikaar et al, 2018; Linder, 2019)

Summary

Introduction

Food production and the planetary boundaries are already beyond the limits of sustainability (Steffen et al, 2015), yet even more pressure on Earth’s carrying capacity is expected with the global population projected to reach 9.2–12.3 billion people by the turn of the century and the rise in living standards (Gerland et al, 2014). Renewable H2 or CO2-derived compounds can be used as an electron donor and/or carbon source for more sustainable microbial protein production (Pikaar et al, 2018; Linder, 2019). Biomass cultivation for microbial protein in general, mainly aims at enhancing the growth rate and (bulk) protein content, rarely targeting nutritious compounds such as essential amino and fatty acids, vitamins and antioxidants or palatability such as taste, odour, texture and appearance.

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Conclusion