Also check https://www.researchgate.net/publication/248511228_Protection_of_fish_feed_made_directly_from_marine_raw_materials_with_natural_antioxidants
Bioethanol is produced by microbs ( saccharomyces cerevisiae) who are sensitived to the mediums' pH
the pH factor of fermentation solution determines the process of sugar reaction to bioethanol. Fermentation solutions that are very acidic or alkaline can inhibit the fermentation process, thus reducing the amount of bioethanol produced. Therefore pH should be regulated