Bio-Transforming Sweet Potato into a Methionine-Rich Aquafeed Ingredient: A Statistical Screening of Saccharomyces cerevisiae Fermentation.

For sustainable aquaculture production, a steady supply of high-quality protein for feed formulations is a challenge for countries with logistical or financial constraints on access to these resources. One of the most sustainable solutions to these challenges is to use microbial fermentation from readily available agricultural waste or crops. The aim of this study was to valorise sweet potatoes, a low-cost and abundant source of carbohydrates, by the baker's yeast Saccharomyces cerevisiae, to produce a protein enriched product suitable for aquaculture use. The Plackett-Burman design was used to effectively screen the key fermentation parameters that influencing the yield and results declared that ammonium sulphate concentration as the most crucial factor affecting the accumulation of protein. Carefully increasing its concentration resulted in a remarkable increase in the crude protein content of the fermented sweet potato (FSP), which increased to 46.24 ± 0.89%, compared with 3.88 ± 0.16% of raw sweet potato. Dietary analysis revealed significant improvements in the amino acid profile, notably a 70.08% increase in the essential amino acid methionine, as well as significant increases in threonine and alanine. This provides a solid basis for countries lacking high-quality protein for aquaculture to explore new local alternatives to achieve the required raw protein concentration from locally available sources..