Reactors and submerged fermentation methods for producing microbe-based products

A method for producing a yeast and/or a yeast metabolite, without contamination, the method comprising:

• adding a culture medium comprising water and a fatty acid source to a submerged fermentation system comprising a chaotic mixing scheme and a sparging system;
• inoculating the submerged fermentation system with a viable yeast to produce a culture;
• adding a sophorolipid or an antibiotic to the submerged fermentation system;
• and
• operating the submerged fermentation system for an amount of time to accumulate a desired cell concentration and/or a desired concentration of the yeast metabolite in the culture, wherein operating the submerged fermentation system comprises mixing the culture using the chaotic mixing scheme and aerating the culture with the sparging system,
• wherein the chaotic mixing scheme comprises an impeller and an external circulation system, and wherein the sparging system comprises multiple stainless steel microporous aerators, said stainless steel microporous aerators comprising a stainless steel pipe attached to an air supply, said stainless steel pipes comprising a plurality of holes 1 micron in diameter or less.