Faculty of Sciences and Technology, Centre for Marine and Environmental Research-CIMA, University of Algarve-Campus de Gambelas, 8005-139 Faro, Portugal.
J Ind Microbiol Biotechnol. 2012 May;39(5):789-97. doi: 10.1007/s10295-011-1079-4. Epub 2012 Jan 20.
The waste materials from the carob processing industry are a potential resource for second-generation bioethanol production. These by-products are small carob kibbles with a high content of soluble sugars (45-50%). Batch and fed-batch Saccharomyces cerevisiae fermentations of high density sugar from carob pods were analyzed in terms of the kinetics of sugars consumption and ethanol inhibition. In all the batch runs, 90-95% of the total sugar was consumed and transformed into ethanol with a yield close to the theoretical maximum (0.47-0.50 g/g), and a final ethanol concentration of 100-110 g/l. In fed-batch runs, fresh carob extract was added when glucose had been consumed. This addition and the subsequent decrease of ethanol concentrations by dilution increased the final ethanol production up to 130 g/l. It seems that invertase activity and yeast tolerance to ethanol are the main factors to be controlled in carob fermentations. The efficiency of highly concentrated carob fermentation makes it a very promising process for use in a second-generation ethanol biorefinery.
角豆加工工业的废料是第二代生物乙醇生产的潜在资源。这些副产物是小角豆颗粒，含有高含量的可溶性糖（45-50%）。在分批和补料分批发酵中，分析了来自角豆荚的高密度糖的酵母发酵动力学，涉及糖消耗和乙醇抑制。在所有的分批运行中，90-95%的总糖被消耗并转化为乙醇，接近理论最大值（0.47-0.50 g/g），最终乙醇浓度为 100-110 g/l。在补料分批运行中，当葡萄糖被消耗时，加入新鲜的角豆提取物。这种添加和随后的稀释导致乙醇浓度降低，使最终乙醇产量增加到 130 g/l。似乎转化酶活性和酵母对乙醇的耐受性是角豆发酵中需要控制的主要因素。高浓度角豆发酵的效率使其成为第二代乙醇生物炼制中非常有前途的工艺。
