Improving single cell protein yields and amino acid profile via mutagenesis: review of applicable amino acid inhibitors for mutant selection

K. Spalvins*, S. Raita, K. Valters and D. Blumberga

Riga Technical University, Institute of Energy Systems and Environment, Azenes street 12/1, LV 1048 Riga, Latvia
*Correspondence: kriss.spalvins@rtu.lv

Abstract:

Single cell protein (SCP) is a good alternative for substituting plant and animal derived dietary proteins, since SCP production is more environmentally friendly, consumes less water, requires smaller land areas and its effect on climate change is much less pronounced than it is in the case of agriculturally derived proteins. Another advantage of SCP is that it is possible to use a wide variety of biodegradable agro-industrial by-products for the cultivation of SCP producing microorganisms. However, to make single cell protein technology more widely available and improve its economic viability in such markets as animal and fish feed industries, it is necessary to improve the protein yields and amino acid profiles in microorganism strains capable of using agro-industrial by-products. One way to improve the strains used in the process is to create and select SCP-rich mutants. In this review authors propose a novel approach to create SCP-rich mutants with improved total protein content and essential amino acid profiles. In this approach amino acid inhibitors are used to create selective pressure on created mutants. It is expected that mutants with the most pronounced growth would either have higher total protein content, increased essential amino acid concentrations or both, when cultivated on selective plates containing one or multiple amino acid inhibitors. This paper reviews the most suitable groups of amino acid inhibitors that could be used for selection of new strains of SCP-producing microorganisms.

Key words:

agricultural residues, amino acid inhibitors, essential amino acids, herbicides, low-cost substrate, microbial protein, mutagenesis