Optimizing Mycoprotein Production using Aspergillus oryzae in Soy Whey Substrate: Effects of Initial pH Adjustment and Salt Supplementation

Abstract

Mycoproteins, that are produced through filamentous fungi fermentation, have gained popularity because of their rich protein content and sustainability as an animal-based protein alternative. However, the cost of the commerciallized mycoprotein exceeds the cost of regular meat. Therefore, scientists are exploring various inexpensive substrates and GRAS fungal strains with high survivability in different substrates to reduce the cost. Aspergillus oryzae, a fungi that has been commonly used in fermented food production, has garnered attention due to its versatility to thrive on diverse substrates, including wastes. In Indonesia, the high demand for tofu causes the industry to dispose of their waste untreated. Thus, developing mycoproteins from Aspergillus oryzae by utilizing soy whey as the cultivation media is a possible solution offered to reduce mycoprotein production cost. Our previous preliminary study shows the capability of A. oryzae to produce biomass (~0.8 g/L) in agitated soy whey media, proved soy whey media capacity to support the fungal growth. However, unsuitable fermentation conditions might explain the low biomass result. Meanwhile, other research papers show that media with adjusted pH or salt supplementation are proven to increase biomass production. Hence, this research aims to investigate the effect of initial pH adjustment and salt supplementation on mycoprotein production using A. oryzae in soy whey media. The optimization was conducted sequentially from pH to salt supplementation. Furthermore, the pH measurement every 24 hours, sugar and acetate analysis, as well as protein analysis were conducted to find the best condition to produce higher biomass concentrations. Result shows that after 3 days of cultivation, the biomass production reach the concentration of 2.52 g/L after initial pH adjustment to pH 5 and 5.06 g/L after salt supplementation experiment, meaning that the biomass concentration have improved ~2.5x and ~5x higher than our first year experiment, respectively.