Improving sweet sorghum for enhanced juice traits and biomass

Biomass & Bioenergy, 2016

The potential of sweet sorghum as an alternative crop for ethanol production was investigated in this study. Initially, the enzymatic hydrolysis of sorghum grains was optimized, and the hydrolysate produced under optimal conditions was used for ethanol production with an industrial strain of Saccharomyces cerevisiae, resulting in an ethanol concentration of 87 g L À1. From the sugary fraction (sweet sorghum juice), 72 g L À1 ethanol was produced. The sweet sorghum bagasse was submitted to acid pretreatment for hemicellulose removal and hydrolysis, and a flocculant strain of Scheffersomyces stipitis was used to evaluate the fermentability of the hemicellulosic hydrolysate. This process yielded an ethanol concentration of 30 g L À1 at 23 h of fermentation. After acid pretreatment, the remaining solid underwent an alkaline extraction for lignin removal. This partially delignified material, known as partially delignified lignin (PDC), was enriched with nutrients in a solid/liquid ratio of 1 g/3.33 mL and subjected to simultaneous saccharification and fermentation (SSF) process, resulting in an ethanol concentration of 85 g L À1 at 21 h of fermentation. Thus, from the conversion of starchy, sugary and lignocellulosic fractions approximately 160 L ethanol.ton À1 sweet sorghum was obtained. This amount corresponds to 13,600 L ethanol.ha À1 .

1995

Potential feedstocks from crop-based energy production systems range from starchy and sugary tuberous crops to woody, oilseed, or herbaceous crops (including corn, sweet and grain sorghums, and several grasses). An important characteristic of biomass crops is that the ratio of energy of the biomass product be large compared to the energy used to pro duce the crop. Because one of the most costly inputs in the latter component is nitrogen (N) fertilizer, any evaluation of potential energy crops must emphasize N inputs. Given its high N requirement, corn is not likely to meet all future ethanol demands. Corn also is limited by the inefficient conversion of starch to etha nol and by environmental and conservation considerations such as suitable land use.

2017

Nowadays, there is a growing interest for alternative energy sources because of the reduction of fossil fuel production. Ethanol used as automotive fuel has increased at least six times in the current century. According to the Renewable Fuels Association, in 2010 the USA bio-refineries generated 13 billion gallons of fuel ethanol and the year before worldwide production reached 19 billion. This noteworthy increment is in its majority based on maize and sugar cane as raw materials (Berg, 2004; Renewable Fuels Association, 2010). The use of these feedstocks has triggered concerns related to food security especially today when the world population has reached 7 billion people. The relatively sudden rise in food prices during 2008, 2010 and 2011 has been attributed mainly to the use of maize for bioethanol even when other factors like droughts or changes in global consumption patterns have also played a major role (World Food Program, 2008). Food price projections indicate that this sit...

ISBN 978-953-51-0008-9

Biological Engineering Transactions

An integrated process has been developed for a sweetsorghum (Sorghum bicolor (L.) Moench) biorefinery in which all carbohydrate components of the feestock are used for production of fuel ethanol and industrial chemicals. In the first step, the juice is extracted from the stalks. The resulted straw (bagasse) then is pretreated using the soaking in aqueous ammonia (SAA) process, which does not result in significant loss of hemicellulose, to enhance subsequent enzyme hydrolysis for production of fermentable sugars. Following pretreatment the straw is hydrolyzed first with commercial enzyme product containing high hemicellulase activity (Accellerase XY). The xylose-rich solution obtained after solid/liquid separation is used for production of value-added co-products using suitable microorganisms. The value-added co-products produced to demonstrate the feasibility include astaxanthin and D-ribose. The residual solids then are hydrolyzed with commercial enzyme product containing high cellulase activity (Accellerase 1500) with the juice extracted in the first step being used as make-up water. By combining the sugar in the juice with the glucose released from the residual solids by enzyme hydrolysis high ethanol concentrations can be achieved, which results in lower distillation cost than if pure water is used for enzyme hydrolysis and subsequent fermentation as normally performed in cellulosic ethanol production.

Biomass and Bioenergy, 2019

Sorghum bicolor (L.) (Moench), which stands out for dry matter yield per hectare, has been considered as potential raw material for biofuels and electricity generation. It has a production cycle of six months, possibility of mechanization of cultivation and harvest and good adaptation to most regions of Brazil. Sorghum genotypes were evaluated for agronomic potential and chemical composition favorable to the production of second-generation ethanol. Three brown midrib (bmr) sorghum mutant hybrids were compared to three conventional hybrids. The bmr sorghum mutant hybrids are associated with reduced lignin content, making these genotypes more promising to the enzymatic conversion processes of the biomass. Sorghum biomass showed a high potential in terms of biomass production, with an average dry matter yield of 26.57 Mg ha −1. Brown midrib sorghum hybrids showed significantly lower lignin contents than conventional hybrids and demonstrated the potential for cellulosic ethanol production.

Journal of Industrial Microbiology & Biotechnology, 2008

Sorghum is a major cereal crop in the USA. However, sorghum has been underutilized as a renewable feedstock for bioenergy. The goal of this research was to improve the bioconversion eYciency for biofuels and biobased products from processed sorghum. The main focus was to understand the relationship among "genetics-structure-function-conversion" and the key factors impacting ethanol production, as well as to develop an energy life cycle analysis model (ELCAM) to quantify and prioritize the saving potential from factors identiWed in this research. Genetic lines with extremely high and low ethanol fermentation eYciency and some speciWc attributes that may be manipulated to improve the bioconversion rate of sorghum were identiWed. In general, ethanol yield increased as starch content increased. However, no linear relationship between starch content and fermentation eYciency was found. Key factors aVecting the ethanol fermentation eYciency of sorghum include protein digestibility, level of extractable proteins, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylose to amylopectin, and formation of amylose-lipid complexes in the mash. A platform ELCAM with a base case showed a positive net energy value (NEV) = 25,500 Btu/gal EtOH. ELCAM cases were used to identify factors that most impact sorghum use. For example, a yield increase of 40 bu/ac resulted in NEV increasing from 7 million to 12 million Btu/ac. An 8% increase in starch provided an incremental 1.2 million Btu/ac.

The Open Agriculture Journal

Background: Sweet sorghum (Sorghum saccharatum (L.) Moench) is a unique crop with great potential to serve both the food and energy industries. It is due to the possibility of (bio)ethanol production both from the juice and biomass of this crop. The sorghum stems juice contains sugar in the levels similar to that of sugarcane. Besides, low cultivation requirements for the sweet sorghum make this crop even more attractive for sugar and ethanol production. In terms of technology, sweet sorghum is seen as a transitional feedstock for the first to the second generation bioethanol production. However, effective technological development of the plant cultivation and processing in the Northern and Central Ukraine is restrained by the lack of a collection of sweet sorghum genotypes and adapted varieties for its large-scale cultivation. Additionally, no evaluations of potential (bio)ethanol productivity have been performed for this region, which is important for efficient implementation of n...

2006

2012

Thesis (M.Sc. Engineering Sciences (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.