Fermentable sugar release from Jatropha seed cakes following lime pretreatment and enzymatic hydrolysis

Composition change of Jatropha seed cake samples was evaluated upon lime pretreatment at 100 °C with different parameters. With a lime dose of 0.2 g and a water content of 10 ml per gram of cake and a treatment period of 1 h, 38.2 ± 0.6% of lignin was removed. However, 65 ± 16% of hemicellulose was also lost under this condition. For all the treatments tested, cellulose content was not affected by lime supplementation. Through further examining total reducing sugar (TRS) release by enzymatic hydrolysis after lime pretreatment, we have found that 0.1 g of lime and 9 ml of water per gram of cake and 3 h pretreatment produced the maximal 68.9% conversion of cellulose. Without lime pretreatment, the highest cellulose conversion was 33.3%. One microalgal species, Schizochytrium limacinum SR21 was able to grow on the hydrolyzates and generate a biomass density of 3.2 g/l in 4 days.