Bioethanol Production from Fermentable Sugar Juice

Sweet sorghum unlike grain sorghum has potential to accumulate sugars in stalks similar to sugarcane. Short duration and lower water requirements of sweet sorghum are other advantages over sugarcane. Sorghum is usually grown in kharif and rabi seasons. As an energy crop, industry demands supply of green cane as raw material through out the year. Hence this agronomic study was conducted to determine suitable time of planting of sweet sorghum under the agro climatic conditions prevailing in India, so that continuous supply of raw material is assured for factory operations through out the year, especially during the lean period of sugarcane crushing. Various physical and chemical characters of plant and stem juice were studied by taking up bimonthly plantings at four locations using 12 genotypes of sweet sorghum in the first year and quarterly plantings at four locations using 10 genotypes (8 genotypes common in both years) in the second year. Of the six plantings, planting during August and April were found to be not suitable for good sweet sorghum yields, therefore, in the second year, four plantings were taken up i.e., June, October, December and February at six locations. The various attributes selected for observations include cane yield, percent brix of stem juice, percent juice extractability, percent total soluble sugars and reducing sugars in the stem juice. Highest green cane yield and percent juice extractability was observed in June planting in all genotypes followed by February, and December in both bimonthly and quarterly plantings. Juice extraction percentage was also highest in June plantings followed by October, April and December plantings. June plantings recorded highest percent brix followed by December and February plantings in bimonthly plantings, while in quarterly planting, highest percent brix and total sugars in juice was observed in February planting followed by planting in June.

Sweet sorghum stalks were used as a low cost carrier for immobilization of Saccharomyces cerevisiae NP 01 to produce ethanol from sweet sorghum juice. The effects on ethanol production of carrier size (6 × 6 × 6 to 20 × 20 × 20 mm3) and initial cell concentrations (5 × 107 to 2 × 108 cells mL−1) for cell immobilization were investigated. The ethanol production medium was the juice containing 230 g L−1 of total sugar without nutrient supplementation. The fermentations were carried out under static conditions in 500-mL air-locked Erlenmeyer flasks at 30 °C. The results showed that the optimum size of sorghum stalk pieces for repeated-batch ethanol production was 6 × 6 × 6 mm3, while the optimum initial cell concentration for the immobilization was 1.0 × 108 cells mL−1. The immobilized yeast under these conditions could be used for at least eight successive batches without any losses of ethanol production efficiencies. The average ethanol concentration, productivity and yield of the eight successive batches were 99.28 ± 3.53 g L−1, 1.36 ± 0.05 g L−1 h−1 and 0.47 ± 0.03 g g−1, respectively.

Effects of harvest time on bioethanol production and bagasse characteristics for combustion and forage in sweet sorghum

Sweet sorghum is a renewable energy crop that offers a sustainable solution to global energy needs as fossil fuels become limited. Its stalks contain fermentable sugars that can be used to produce bioethanol, a cleaner alternative to fossil fuels. Sweet sorghum grows quickly, requires less water than many other energy crops, and can be cultivated on marginal land. Using sweet sorghum for energy helps reduce greenhouse gas emissions and supports rural economies. Therefore, sweet sorghum is a promising renewable resource for future energy production. Sweet sorghum has several important biofuel applications that support renewable energy production. The sugary juice from its stalks is mainly used to produce bioethanol through fermentation. Its fibrous residue (bagasse) can be used to generate electricity or heat through biomass energy. Sweet sorghum can also be processed into biogas by anaerobic digestion. In addition, its residues can be converted into bio-based products, making it a versatile and sustainable biofuel crop.

Bioethanol produced from renewable resource has potential to solve environmental pollution and to satisfy the need of demand and supply. It favours the use of nonfood lignocellulosic materials. Ethanol produced from plant materials can sustain the economy by reducing cost of imported petroleum, emitting neutral CO2. Moreover, it enhances the economy by providing value added market opportunities for transportation and agricultural sector. Therefore, the objective of the study was to investigate bioethanol production from stalk residues of Chiquere and Gebabe varieties of sweet sorghum collected from West Arsi Zone, Ethiopia. Response surface methods with a three factor (inoculum size, pH, and dilution rate) with triplicate run by using the Box–Behnken method was referred. The experiment employed dilute acid hydrolysis, because it is an easy and productive process by treating the stalks with 4% of sulfuric acid for effective hydrolysis of substrate. Finally, the fermentation was carried out at 30°C for 72 hours on a shaker at 180 rpm by using Saccharomyces cerevisiae. The significance of the result was evaluated by using ANOVA, where P values <0.05 were considered statistically significant. In the process, maximum yield of ethanol was obtained at an inoculum size of 5% (22.40%), pH level of 4.0 (21%), and dilution rate at 10 ml (21.46%). Very low yeast inoculum size and dilution factor have positive effect on the yield of ethanol, whereas very high dilution rate produced negative impact on ethanol production. FTIR spectroscopy peaks associated with O-H, C-O, and C-H stretching vibrations confirmed the presence of ethanol obtained from sweet sorghum stalks. The results of our study indicated that, being available in bulky amounts and nonedible material, sweet sorghum stalks can serve as potential feedstock for bioethanol production in developing countries such as Ethiopia.

Sweet sorghum is being investigated as a feedstock for ethanol production in semi-arid countries. It can be grown with fewer inputs than other energy crops. In Iran, due to long growing season, ethanol is produced from both sweet sorghum stem and grain. In other countries, ethanol is not produced from sweet sorghum grain due to low grain yield or short growing season. The purpose of this study was to maximize ethanol production from both stem and grain of sweet sorghum. Four planting dates (July 5, July 14, July 25 and August 4) and three nitrogen levels (50, 100 and 150 kg/ha urea) were assigned to the main and subplots, respectively. Plants were harvested at physiological maturity. Stem measurements were: stalk height, stalk diameter, stalk fresh yield, brix value, sucrose content, total sugar and ethanol yield and grain measurements were: number of grain per panicle, 1000 grain weight, grain yield, biological yield, harvest index and ethanol yield. Stem measurements were highest in July 5 planting and lowest in August 4 planting, while grain measurements were highest and lowest in August 4 and July 5 plantings, respectively. Stem and grain measurements in July 15 and July 25 were intermediate. More grain yield, 1000 grain weight and number of grain/panicle were obtained with the application of 150 kg/ha urea than the other two nitrogen levels. Based on the results, in order to obtain the highest ethanol yield from both stem and grain, it is suggested to plant sweet sorghum as early as possible and apply 150 kg/ha urea. &nbsp; Key words: Sweet sorghum, temperature, planting date, ethanol production, nitrogen levels.

This study investigates the composition, hydrolysis, fermentation, kinetic studies and optimization by response surface methodology (RSM) of ten different lignocellulosic materials in ethanol production using enzymatic hydrolysis of isolated Trichoderma reesei and Aspergillus niger and fermentation by Zymomonas mobilis and Saccharomyces cerevisiae. Proximate and ultimate analyses reveal that sugarcane bagasse and rice husk are ideal feedstocks due to their high volatile matter, low moisture, and ash content, offering more fermentable carbohydrates. The highest glucose concentrations were achieved from sugarcane bagasse (0.5689 g L-1) using T. reesei and from rice husk (0.5803 g L-1) using A. niger. Pretreatment increased glucose yields, with rice husk (RHAn) yielding 9.3 g L-1 ethanol in 60 h and sugarcane bagasse (SBTr) yielding 8.1 g L-1 in 48 h, and the particle size reduction to 75 μm enhanced glucose yields due to increased surface area. Kinetic models, including the Monod and Michaelis-Menten models, were used to describe ethanol production, with RHAn exhibiting the highest growth parameters. This study reports optimized ethanol production that achieved maximum yields under controlled conditions, further supporting the feasibility of large-scale bioethanol production.

Assessing viability of bio-ethanol production from sweet sorghum in India

Sweet sorghum is a C4 grass which is traditionally cultivated for making syrup from the sugars in the stalks. Sweet and grain sorghum are in the same species, Sorghum bicolor (L.) Moench. In optimum conditions, sweet sorghum can grow 4.5 meters tall and produce 45 to 110 Mg of fresh weight biomass per hectare with less N and water than maize. Ethanol can be produced from sweet sorghum stalks by extracting the juice and fermenting the sugars with yeast. Bagasse remaining after extraction can be fed to livestock or converted to useable energy by burning to produce steam for generating electricity, anaerobic digestion to make methane, or reacting with oxygen at high temperature to produce synthetic gas. Sweet sorghum can be grown in most climates. Some cultivars will grow as far north and south as the 45° latitude. It is normally grown as an annual crop. But, in warm climates, a single seed planting can be managed for two or three years by leaving lower stalks and roots at harvest to produce new tillers for the next growing cycle. Rotating sweet sorghum in alternate years with a non-grass crop is an effective management tool for reducing insect, weed, and disease pests. Nitrogen fertilizer can often be reduced when sweet sorghum is planted after a legume crop such as soybean. Most of the sugar for syrup and ethanol from sweet sorghum is currently produced with open pollinating cultivars. Recently, hybrid sweet sorghums with increased sugar content and biomass yield have been developed in India, China, and the United States.

The development and implementation of waste-free resource- and energy-saving technologies is the basis for increasing pr o duction efficiency, which will help produce a comprehensive solution to the problem of resource supply of the economy and environmental protection. The production of food products, in particular starch, from non-traditional raw materials is increasingly attracting the attention of both researchers and manufacturers, as the population becomes more aware of the impact of healthy nutrition. This article provides a detailed review of current research on the use of cassava ( Manihot esculenta) in the food and processing industries. During the literature review, the ability to use waste-free technology for cassava processing was cons i dered, namely, obtaining food starch and flour from this type of raw material. Cassava flour, and accordingly, products from it, are suitable for consumption by people suffering from gluten intolerance, as well as people who seek to eat healthy food. This raw material is also promising for obtaining food starch. Waste s generated in the agro-industrial complex make up a significant share in the field of bioenergy production, including their consumption in the production of ethanol and biofuels, which has been the focus of attention of many researchers over the past decade due to the depletion of fossil oil reserves. Biofuel production from cassava starch began at the end of the last century, and the use of cassava residues, such as peel, bagasse, stem, root and leaves, is currently being intensively studied by researchers to identify their potential in biofuel production. Analysis of the scientists' r e search showed that it is worth highlighting several main areas of work on the use of cassava for partial or complete replacement of wheat flour with cassava flour in the production of bakery products, the production of starch for the food industry, biodegrad a ble material for food packaging and the production of bioethanol. The data obtained contain practical value regarding the poss i bility of using cassava and its waste-free processing, which is a relevant issue today.

Compared to other potential feedstocks such as sugarcane, sugar beet, maize, and watermelon, sweet sorghum possesses higher levels of directly fermentable reducing sugars within the culm and the ability to accumulate high biomass under low‐input production systems. In addition, it is tolerant to drought and has more efficient utilization of solar radiation and nitrogen‐based fertilizers than maize and sugar cane on marginal lands that are not optimal for food production. These collectively make sweet sorghum to be considered with huge potential as a biofuel crop. Novel phenotypes generated during plant domestication and continued crop improvements via artificial selection constitute the domestication syndrome (Am. J. Bot., 101, 2014, 1711). Here, we draw an analogy and introduce the term the biofuel syndrome to refer to a suite of sweet sorghum traits, such as plant architecture (root, leave, and stem), flowering time and maturity as well as biomass bioconversion efficiency, that are associated with biofuel production and distinguish it from grain and forage sorghum traits. We discuss the biofuel syndrome amenable for targeted genetic modulation and what is currently known about the genetics and genomics of these traits as a potential route to optimize sweet sorghum for biofuel production. Continuous availability of sweet sorghum, transport and storing much mass and minimizing the postharvest loss of fermentable sugars are fundamental to exploiting sweet sorghum as a bioenergy crop. Due to the relatively short history of sweet sorghum breeding, we consider the development of ideotypes adapting to various phenological requirements to maximize the rapid deployment of sweet sorghum for biofuel production.

Bioethanol production by mangrove-derived marine yeast, Sacchromyces cerevisiae

Sweet pearl millet [Pennisetum glaucum (L.) R. Br.] and sweet sorghum [Sorghum bicolor (L.) Moench], previously tested for ethanol production, were evaluated as high sugar crops for animal feeds to possibly replace silage corn (Zea mays L.). We compared the forage yield, nutritive value, and ensilability of one hybrid of sweet pearl millet and two of sweet sorghum to a locally adapted silage corn hybrid in five Canadian ecozones. Forage yields of sweet pearl millet and sorghum were similar to that of silage corn in the Boreal Shield, Mixedwood Plain, and Atlantic Maritime ecozones, greater in the Prairies, and lower in the Pacific Maritime ecozone. Across sites, forage dry matter concentration was less for sweet pearl millet (289 g kg−1) and sweet sorghum (245 g kg−1) than for silage corn (331 g kg−1). Sweet pearl millet had a lower total digestible nutrient (TDN) concentration (452 g kg−1 DM) and aNDF digestibility (NDFd) than sweet sorghum and silage corn along with greater neutral detergent fibre (aNDF) and water-soluble carbohydrate (WSC) concentrations than silage corn. Sweet sorghum had greater aNDF and WSC, lower starch, and similar TDN (534 g kg−1 DM) concentrations, but greater NDFd compared with silage corn. Sweet pearl millet and sorghum fermented as well as silage corn, reaching low pH values and acceptable concentrations of lactic and volatile fatty acids. Sweet sorghum is therefore a viable alternative to silage corn in Canada except in the Pacific Maritime ecozone, but early-maturing hybrids with acceptable DM concentration at harvest are required.

Current fossil fuel reserves cannot keep up with the world’s need for fuel, leading to a global energy crisis. The issue raises attention to renewable energy sources. Indonesia has committed to using 15% bioethanol in gasoline mixture by 2025, as outlined in Presidential Decree No. 5 of 2006. This article discusses past studies on sweet sorghum plants in their use as a raw material for bioethanol production from various aspects. The study shows that sweet sorghum juice has a high potential to be converted into bioethanol due to its high sugar content. Pretreated sweet sorghum seeds and bagasse also have great potential to be converted into bioethanol due to their rich oligomer and polymer sugar content. The main challenge of producing bioethanol from sweet sorghum is the low economic competitiveness of utilizing sweet sorghum as an energy crop compared to using sweet sorghum as a food crop. The present study focuses on the mass balance analysis of bioethanol production from sweet sorghum. It is expected that the results of the present study may give a preliminary overview of the bioethanol production potential from sweet sorghum.

BackgroundSugar-sweetened beverages have obesogenic and diabetogenic effects ascribed to free sugars. These include added sugars and naturally occurring sugars in juices. A meta-analysis indicates that some foods with added sugars are associated with lower type 2 diabetes rates. To expand the evidence relevant to free sugars from solid sources, we examined a young to middle-aged population with respect to overweight and gestational diabetes (GDM) outcomes.MethodsWe studied female participants (12–50 years old) from the 2004–2005 Canadian Community Health Survey 2.2 (CCHS) with data linked to the hospital Discharge Database (DAD) until 2017, providing 13 years of follow-up. We estimated free sugars by solid and liquid sources from 24-h dietary recalls as percent total energy intake (TE%), and computed body mass index (BMI). We applied ICD-10 diagnostic codes for deliveries and GDM to DAD. We conducted multivariable logistic regression analyses to evaluate associations between free sugars with overweight at baseline (cross-sectional component) and, in those who delivered, with GDM during follow-up (nested case control component). We compared those with consumption above versus below various thresholds of intake for free sugars, considering solid and liquid sources separately (2.TE%, 5TE%, 10TE% and 15TE% thresholds).ResultsAmong 6305 participants, 2505 (40%) were overweight, defined as BMI ≥ 85th percentile below 18 years and BMI ≥ 25 kg/m2 for adults. Free sugars from solid sources were associated with lower odds of overweight above versus below the 2.5TE% (adjusted odds ratio [adjOR] 0.80, 95%CI 0.70–0.92), 5TE% (adjOR 0.89, 95%CI 0.79–0.99), and 10TE% (adjOR 0.86, 95%CI 0.75–0.97) thresholds. Free sugars from liquid sources were associated with greater odds of overweight across the 2.5TE% (adjOR 1.20, 95%CI 1.07–1.36), 10TE% (adjOR 1.17, 95%CI 1.02–1.34), and 15TE% (adjOR 1.43, 95%CI 1.23–1.67) thresholds. There were 113 cases of GDM among the 1842 women who delivered (6.1%). Free sugars from solid sources were associated with lower odds of GDM above versus below the 5TE% threshold (adjOR 0.56, 95%CI 0.36–0.85).ConclusionsOur findings support limiting free sugars from liquid sources, given associations with overweight. We did not identify adverse associations of free sugars from solid sources across any of the thresholds examined.