Exploring the Bioethanol Production Potential of Miscanthus Cultivars

Abstract

Miscanthus is a fast-growing perennial grass that attracts significant attention for its potential application as a feedstock for bioethanol production. This report explores the difference in the lignocellulosic composition of various Miscanthus cultivars, including Miscanthus × giganteus cultivated at the same location (mainly Lincoln, UK). It also assesses the sugar release profiles and mineral composition profiles of five Miscanthus cultivars harvested over a growing period from November 2018 to February 2019. The results showed that Miscanthus × giganteus contains approximately 45.5% cellulose, 29.2% hemicellulose and 23.8% lignin (dry weight, w/w). Other cultivars of Miscanthus also contain high quantities of carbohydrates (cellulose 41.1–46.0%, hemicellulose 24.3–32.6% and lignin 21.4–24.9%). Pre-treatment of Miscanthus using dilute acid followed by enzymatic hydrolysis released 63.7–80.2% of the theoretical glucose content. Fermentation of a hydrolysate of Miscanthus × giganteus using Saccharomyces cerevisiae NCYC2592 produced 13.58 ± 1.11 g/L of ethanol from 35.13 ± 0.46 g/L of glucose, corresponding to a yield of 0.148 g/g dry weight Miscanthus biomass. Scanning electron microscopy was used to study the morphology of raw and hydrolysed Miscanthus samples, which provided visual proof of Miscanthus lignocellulose degradation in these processes. The sugar release profile showed that a consequence of Miscanthus plant growth is an increase in difficulty in releasing monosaccharides from the biomass. The potassium, magnesium, sodium, sulphur and phosphorus contents in various Miscanthus cultivars were analysed. The results revealed that these elements were slowly lost from the plants during the latter part of the growing season, for a specific cultivar, until February 2019.

Using Machine Learning to Identify the Potential Marginal Land Suitable for Giant Silvergrass (Miscanthus × giganteus)

“…There are only a few studies working on the potential land resources for growing giant silvergrass. Xue et al's estimation through multi-factor analysis shows that 172 million hectares of marginal land are available for producing giant silvergrass [15], which is larger than our results of 129.64 million hectares. This is because the resulting values obtained from the multi-factor analysis are 0 and 1, representing unsuitability or suitability for planting giant silvergrass, respectively, and therefore, they fail to reflect the spatial variability of land resources suitable for giant silvergrass [46,47].…”

“…In terms of identifying unsuitable land resources for giant silvergrass cultivation, the urban, barren, and cropland were excluded for their unavailability [20]. In addition, areas with low temperatures (temperatures < −23 • C) or low precipitation (precipitation < 400 mm) were also deemed unsuitable for giant silvergrass [15]. Therefore, the same number of pseudo-samples were randomly drawn from these regions.…”

“…It can survive in a wide range of climatic conditions, with temperatures ≥ −23 • C and precipitation ≥ 400 mm [13,14]. In addition, it contains high quantities of carbohydrates, including approximately 45.5% cellulose, 29.2% hemicellulose, and 23.8% lignin (dry weight, w/w) [15].…”

Evaluation of Chemical Composition of Miscanthus × giganteus Raised in Different Climate Regions in Russia

“…The use of Miscanthus as the carbon resource can replace fossil fuels, with no serious damage to the environment [ 2 ]. In China, Miscanthus has already become in-demand for bioenergy development [ 14 ]. In the UK, Miscanthus is also touted as a popular bioenergy feedstock because of high yields (8–32 ton/ha) and a high energy output (140–560 GJ/ha) compared to the other raw materials [ 9 , 14 ].…”

“…In China, Miscanthus has already become in-demand for bioenergy development [ 14 ]. In the UK, Miscanthus is also touted as a popular bioenergy feedstock because of high yields (8–32 ton/ha) and a high energy output (140–560 GJ/ha) compared to the other raw materials [ 9 , 14 ]. It is believed that Miscanthus is able to shorten and, in perspective, replace wood in the industry if more eco-benign (green) technologies are employed, particularly without sulfur and chlorine chemicals and hence with a minimum negative impact on the environment [ 15 ].…”