Sugar cane bagasse medium optimization to SCP protein production by a Candida tropicalis strain from Brazilian biome

The production of bioethanol from biomass is one of the viable alternatives to the use of bagasse from sugarcane. From the lignocellulosic material deconstruction, it is possible to obtain the free form sugar to be converted into bioethanol. Xylose, which is one of these sugars, is not converted into ethanol by conventional yeast (Saccharomyces cerevisiae). Even the few genera of yeasts that have the ability to turn that sugar into ethanol don´t show an efficient behavior in this conversion. Then the use of sugar for the production of SCP (Single cell protein) could be an interesting alternative to xylose destination. In this work we optimized in shake flask conditions the quantities of: xylose and yeast extract to formulate an industrial media (xylose syrup from the hydrolysis of bagasse from sugarcane) for protein production by a Candida tropicalis strain isolated from a Brazilian biome. The optimization was carried out using central composite rotational design (CCRD). The results show that the yeast extract within the studied range (5.2 to 10.8 g / L) does not affect the amount of protein produced. For the xylose concentration the best results are obtained when use is made of 4.3 g / L of sugar. When grown in this xylose concentration the yeast was able to produce 49.5% of protein. This result shows to be encouraging since in optimized synthetic medium (more expensive) the same yeast was able to produce 53.8% of protein.