Production of single cell protein from sugarcane molasses for feed protein and techno-economic analysis

Abstract

The livestock industry has undergone rapid expansion in recent years, resulting in an increased demand for feed protein. The production of plant and animal proteins cannot sustainably meet the expanding demand for protein, and the development of single cell protein (SCP) as a feed protein is a promising avenue. Molasses is a cheap and nutritious by-product of sugar production from sugarbeet and sugarcane, and is one of the common substrates available to microorganisms. In this study, R. glutinis As 2.703 was used to produce SCP by fermentation with inexpensive carbon source molasses and nitrogen source corn steep liquor instead of glucose and yeast extract, respectively. The results revealed that when the concentration of molasses in the substrate was 61 g/L, the biomass concentration reached 21.0 g/L, and the protein, lipid, carotenoid contents in dry cell were 30.4 %, 7.8 %, and 31.7 μg/g, respectively. SuperPro Designer was used to simulate the process and carry out the economic analysis for producing SCP from 100,000 tons of molasses annually. A plant of this size could produce 32,908 tons/year of SCP at cost of 988.2 USD/ton with payback period of 6.3 years. Sensitivity analysis showed that the selling price of SCP has the greatest impact on the economics of industrial production of SCP, and that by increasing its protein and carotenoid content, its value can be increased, and further increasing its selling price is the key to achieving industrialisation. This study provides new ideas to cope with the future protein feed crisis.