Improving lipid production from bagasse hydrolysate with Trichosporon fermentans by response surface methodology

• Published in: New biotechnology 2012-02, Vol.29 (3), p.372-378
• Main Authors: Huang, Chao, Wu, Hong, Li, Ri-feng, Zong, Min-hua
• Format: Article
• Language: English
• Subjects: activated carbon; Bagasse; biodiesel; Biofuels; carbon nitrogen ratio; cell growth; Cellulose - chemistry; Cellulose - pharmacology; Charcoal; Charcoal - chemistry; Diesel; Fermentation; Hydrogen-Ion Concentration; Hydrolysates; Hydrolysis - drug effects; Inoculum; lignocellulose; lipid content; Lipids; Lipids - biosynthesis; Lipids - chemistry; Lipids - isolation & purification; pH effects; Polystyrenes - chemistry; Polyvinyls - chemistry; Resins; response surface methodology; Sugar; sugarcane bagasse; sugars; Trichosporon; Trichosporon - growth & development; Trichosporon - metabolism; yeasts
• ISSN: 1871-6784; 1876-4347
• DOI: 10.1016/j.nbt.2011.03.008

Oleaginous yeast Trichosporon fermentans was proved to be able to use sulphuric acid-treated sugar cane bagasse hydrolysate as substrate to grow and accumulate lipid. Activated charcoal was shown as effective as the more expensive resin Amberlite XAD-4 for removing the inhibitors from the hydrolysate. To further improve the lipid production, response surface methodology (RSM) was used and a 3-level 4-factor Box–Behnken design was adopted to evaluate the effects of C/N ratio, inoculum concentration, initial pH and fermentation time on the cell growth and lipid accumulation of T. fermentans. Under the optimum conditions (C/N ratio 165, inoculum concentration 11%, initial pH 7.6 and fermentation time 9 days), a lipid concentration of 15.8g/L, which is quite close to the predicted value of 15.6g/L, could be achieved after cultivation of T. fermentans at 25°C on the pretreated bagasse hydrolysate and the corresponding lipid coefficient (lipid yield per mass of sugar, %) was 14.2. These represent a 32.8% improvement in the lipid concentration and a 21.4% increase in the lipid coefficient compared with the original values before optimization (11.9g/L and 11.7). This work further demonstrates that T. fermentans is a promising strain for lipid production and thus biodiesel preparation from abundant and inexpensive lignocellulosic materials.