Bioethanol Production from Fermentable Sugar Juice

Abstract

Bioethanol production from renewable sources to be used in transportation is now an increasing demand worldwide due to continuous depletion of fossil fuels, economic and political crises, and growing concern on environmental safety. Mainly, three types of raw materials, that is, sugar juice, starchy crops, and lignocellulosic materials, are being used for this purpose. This paper will investigate ethanol production from free sugar containing juices obtained from some energy crops such as sugarcane, sugar beet, and sweet sorghum that are the most attractive choice because of their cost-effectiveness and feasibility to use. Three types of fermentation process (batch, fed-batch, and continuous) are employed in ethanol production from these sugar juices. The most common microorganism used in fermentation from its history is the yeast, especially, Saccharomyces cerevisiae, though the bacterial species Zymomonas mobilis is also potentially used nowadays for this purpose. A number of factors related to the fermentation greatly influences the process and their optimization is the key point for efficient ethanol production from these feedstocks.

Influence of Sowing Times, Densities, and Soils to Biomass and Ethanol Yield of Sweet Sorghum

“…However, lignocellulosic materials are being studied and developed in laboratory because of low efficacies of economic and ethanol yield [49]. Current industrial fermentation for fuel ethanol production uses two types of feedstocks including free fermentable sugars and starch, juices containing free sugars are more economical than starch feedstocks as the former can directly be employed in fermentation without any prior treatment.…”

INHIBITION OF THE GROWTH OF TOLERANT YEAST Saccharomyces cerevisiae STRAIN I136 BY A MIXTURE OF SYNTHETIC INHIBITORS

“…Moreover, the strain was not able to utilize xylose as a carbon source as its concentration remained at 50 g.l -1 at the end of cultivation period. Factors influencing bioethanol production include temperature, sugar concentration, pH, fermentation time, agitation rate and inoculum size (Zabed et al 2014). Ethanol production increased rapidly when the strain started to utilize the glucose.…”

Production of Bioethanol from Agricultural Wastes Using Residual Thermal Energy of a Cogeneration Plant in the Distillation Phase

“…In United States it is used as 10% solution in gasoline (E-10) while in Brazil it is used both blended ( 24% ethanol, 76% gasoline) and hydrated in Flexible-fuel vehicles [5]. Others mixtures are E-15 (15% ethanol , 85% gasoline) and E-85 (85% ethanol e 15% gasoline).…”

“…The temperatures that allow a good microbial growth and a good ethanol yield generally range between 20°C and 35°C. As fermentation is an exergonic process, a particular attention is required to fermentation temperature control [5]. Then, to maximize the ethanol yield, yeast strains resistant to high temperatures should be chosen; this is the best choice for bioethanol production, allowing high yields and low costs, while it should be not suitable for fermentations aimed to reach alcoholic beverages, because sensory properties could be compromised.…”

“…To remove the remaining water, special process are required to reach anhydrous ethanol, that include: chemical dehydration process, dehydration by vacuum distillation process, azeotropic distillation process, extractive distillation processes, membrane processes, adsorption processes and diffusion distillation process [15]. The evaluation of the energy balance of bioethanol production reveals that most of the energy is required for the distillation, also because of the low concentration of ethanol in the fermented broth [5]. Energy consumption can be reduced during distillation if lower heating is necessary; this can be reached using residual thermal energy from other processes to warm the fermented broth.…”