Pilot scale production of high-content mycoprotein using Rhizopus microsporus var. oligosporus by submerged fermentation and agro-industrial by-products.

While mycoprotein has gained traction as a human food source, its potential as a nutrient for animals remains largely unexplored. The mycoprotein-producing Rhizopus microsporus var. oligosporus, a fungus traditionally used for human food in Indonesia, is promising. It could revolutionise animal nutrition once it is Generally Recognized as Safe (GRAS) and is a biosafety level 1 (BSL1) organism. To enhance sustainably, we propose using sugar cane molasses (SM) and corn steep liquor (CSL) as nutrient sources. Also, we investigated the growth of R. microsporus var. oligosporus in five 14 L external-loop airlift bioreactors using CSL as the sole nutrient source. After 96 h of fermentation, at 25 °C and 0.5 vvm, the mycelium produced had an average biomass yield of 38.34 g L-1, with 70.18 % (m v-1) crude protein (mycoprotein). This bioprocess, which is scalable and economically viable, produces high amounts of mycoprotein for animal feed using CSL, a cost-effective agro-industrial by-product, providing a practical solution to the growing demand for animal protein.

Ethanol from rice byproduct using amylases secreted by Rhizopus microsporus var. oligosporus. Enzyme partial purification and characterization.

A three-stage bioethanol bioprocess was developed. Firstly, amylases were obtained from Rhizopus microsporus var. oligosporus using wheat bran in solid-state fermentation. Secondly, amylases hydrolyzed a rice byproduct to make a glucose-rich solution, and this sugar was finally metabolized by Saccharomyces cerevisiae to produce bioethanol. Besides, the secreted enzymes were also partially purified and characterized. The amylase activity (AA) in the crude extract was 358 U/g substrate, and the partially purified enzyme showed the best activity in the 4.0-5.5 pH range. A wide pH stability range (3.5-8.5) was confirmed. The amylase was thermostable up to 60 °C. The ion Mn+2 (10 mM) improved by 60% the AA. There was a 54.9% yield in the conversion of rice residues into reducing sugars in 10 h. The glucose-rich solution was undergone fermentation by S. cerevisiae and showed high ethanol efficiency, 95.8% of the theoretical value. These results suggested a promising technology for bioethanol production.