Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
World J Microbiol Biotechnol. 2013 Aug;29(8):1509-15. doi: 10.1007/s11274-013-1317-1. Epub 2013 Mar 19.
Tropical maize is an alternative energy crop being considered as a feedstock for bioethanol production in the North Central and Midwest United States. Tropical maize is advantageous because it produces large amounts of soluble sugars in its stalks, creates a large amount of biomass, and requires lower inputs (e.g. nitrogen) than grain corn. Soluble sugars, including sucrose, glucose and fructose were extracted by pressing the stalks at dough stage (R4). The initial extracted syrup fermented faster than the control culture grown on a yeast extract/phosphate/sucrose medium. The syrup was subsequently concentrated 1.25-2.25 times, supplemented with urea, and fermented using Saccharomyces cerevisiae for up to 96 h. The final ethanol concentrations obtained were 8.1 % (v/v) to 15.6 % (v/v), equivalent to 90.3-92.2 % of the theoretical yields. However, fermentation productivity decreased with sugar concentration, suggesting that the yeast might be osmotically stressed at the increased sugar concentrations. These results provide in-depth information for utilizing tropical maize syrup for bioethanol production that will help in tropical maize breeding and development for use as another feedstock for the biofuel industry.
热带玉米是一种替代能源作物，正在被考虑作为美国中北部和中西部地区生产生物乙醇的原料。热带玉米具有优势，因为它的茎秆中产生大量可溶糖，产生大量生物质，并且比谷物玉米需要更少的投入（例如氮）。在面团阶段（R4）通过压榨茎秆提取包括蔗糖、葡萄糖和果糖在内的可溶糖。初始提取的糖浆比在酵母提取物/磷酸盐/蔗糖培养基上生长的对照培养物发酵得更快。然后将糖浆浓缩 1.25-2.25 倍，添加尿素，并使用酿酒酵母发酵长达 96 小时。最终获得的乙醇浓度为 8.1%（v/v）至 15.6%（v/v），相当于理论产量的 90.3-92.2%。然而，随着糖浓度的增加，发酵生产率下降，这表明酵母在增加的糖浓度下可能受到渗透压的影响。这些结果为利用热带玉米糖浆生产生物乙醇提供了深入的信息，这将有助于热带玉米的培育和发展，作为生物燃料行业的另一种原料。
