Yeast protein Weighs Global Food

Climate change poses challenges as a fait accompli as the decreasing arable land, water scarcity, and increasing greenhouse gas emissions, so that the threat of food deficiency has happened in the area now and then. Published data by Concern and Welthungerhilfe, the Global Hunger Index(GHI) gives us current world hunger facts in 2023, even the world produces enough food to feed for 8 billion people, yet 828 million people go hungry every day, 2.3 billion people, 29.6% of the global population, don't have adequate access to food.

To attenuate the pressure on global food maintenance, yeast Single Cell Protein (SCP) is a type of protein derived from extract of the microorganism that is considered to be a sustainable protein source that can help mitigate the negative impacts of climate change, be produced consistently regardless of climate conditions, and be a solution by being more resource-efficient and environmentally friendly compared to traditional husbandry.

Yeast proteins, as a kind of single cell protein and especially from Saccharomyces cerevisiae, are safe, natural, and with balanced amino acid composition. It is now used as a nutritional supplement or as an auxiliary material in food formulas. Yeast protein is a promising substitute for meat products due to its rich amino acid content, making it a valuable component of a healthy and flavored diet.

Three main obstacles to the widespread utilization of yeast SCP are high purine content, which will cause human gout and renal stone formation, the difficulty of digesting yeast cell walls that decreases the protein yield and nutrient bioavailability, and the final, high production cost limits its scalability. To achieve effective degradation of nucleic acids in yeast, the current process collects yeast cells and triggers autolysis at 50°C and pH 5.0. After autolysis starts, both nuclease and protease are activated to degrade the nucleic acid (RNA) into nucleotides and proteins into polypeptides, oligopeptides and amino acids, unable to obtain yeast whole protein invariably. The three problems in industrial application of yeast SCP have not yet been resolved.

In face to these imminent problems, Quorn Company in the UK uses a fungus, Fusarium venenatum, to collecte fungal mycelium heated at 64°C for 20-30 minutes by a  rapid heating process(<10s). The nucleases in the mycelium are activated to degrade the nucleic acid, but  the proteases are muted at the high temperature. After the nucleic acid degrades into single nucleotides or oligonucleotides (RNA-depleted),  the fungal protein is harvested by vacuum filtration.

The protocol is also modified by us to prioritize on a coupling temperature-nuclease method to address the problems and extend its application in yeast.  A process has been designed to obtain an exclusively lengthy and depurinated protein mixture , that is, fermentation and collection of yeast cells, inactivation autolysis at high temperature 85-100 °C, plus complete mechanical disruption , addition of complex nucleases to break down nucleic acids, separation and purification to reap four final products as follow, cell wall polysaccharides, whole cell proteins, nucleotides and cell extract rich in small molecule nutrients such as B vitamins and coenzymes. These four categories of products can yield human alternative proteins, fibers, dietary lipids and other pharmaceutical products and health-promoting compounds, all of which attribute to prominently decrease the cost of the manufactures, thereby the consequences of solving the three major obstacles to industrialization are under way.  Next, we aim to improve microbial-based foods, including nutritional whole foods, alternatives to animal products (meat, dairy and eggs), and ingredients (flavours or nutraceuticals).

Finally, extensively sharing the public about the benefits of SCP, its nutritional value, and its role in food security and environmental sustainability can help familiarize consumers with SCP and increase its adoption. Informative knowledge and resources can accelerate the progress. Beyond that, after further studies on the safety and nutritional aspects of SCP, addressing concerns such as allergenicity and potential contaminants will alleviate public apprehensions. A vast of recognition will generate a commonplace to drive the new food requirement in its wake.

Written by  Dr. Haining Jin  and  Dr. Bin Xu