Cultivation of Candida langeronii in sugar cane bagasse hemicellulosic hydrolyzate for the production of single cell protein

Sugar cane bagasse hemicellulosic fraction was hydrolysed by treatment with 70 mg of sulphuric acid per gram of dry mass at 125 degrees C for 2 h. The hydrolysate was used as the substrate to grow Candida langeronii RLJ Y-019 at 42 degrees C; initial pH 6.0; stirring at 700 rev/min and aeration at 1.0 and 2.0 v/v/min. The utilization of D-xylose, L-arabinose, and acetic acid were delayed due to the presence of D-glucose, but after D-glucose depletion the other carbon sources were utilized. The kinetic parameters calculated for both cultivations at 1.0 and 2.0 v/v/min included: maximum specific growth rate (mu(max)) of 0.29 +/- 0.01 h(-1) and 0.43 +/- 0.016 h(-1), yields (Y-x/s) of 0.36 +/- 0.012 and 0.40 +/- 0.012 g(x)/g(s) and productivity (Q(x)) of 0.81 +/- 0.016 and 0.97 +/- 0.012 g(x)/l/h, respectively, and compared favourably with published results obtained with Candida utilis and Geotrichum candidum. Candida langeronii appeared superior to C. utilis for biomass production from hemicellulose hydrolysate, in that it utilized L-arabinose and was capable of growth at higher temperatures. The biomass contained 48.2, 1.4, 5.8 and 23.4% of total protein, DNA, RNA and carbohydrate, respectively and contained essential amino acids for animal feed.