Brachiaria brizantha Grass as a Feedstock for Ethanol Production

Abstract

Different lignocellulosic biomasses are found worldwide and each country has its own important industrial crop that can be converted into high-value products, such as ethanol. Therefore, evaluation of new biomasses to be used in biorefineries is important to decrease the dependence on non-renewable resources and to guarantee sustainable development. This work evaluated Brachiaria brizantha, a grass commonly used as animal forage, and the standard biomass for 2G-ethanol, sugarcane bagasse. The chemical compositions of both biomasses were determined and different times and temperature of acid pretreatment were tested. Morphological analysis via scanning electron microscopy showed more deconstructed fibers after harsher biomass pretreatments. Simultaneous saccharification and fermentation of pretreated Brachiaria brizantha presented higher efficiency than when using sugarcane bagasse as the carbon source. A biomass conversion of 46 % was achieved when Brachiaria brizantha grass was pretreated with 2% sulfuric acid for 60 minutes. Moreover, fermentation was not impaired by the inhibitors furfural and hydroxymethylfurfural. It was concluded that Brachiaria brizantha is a promising biomass for ethanol production.

Comparative Analysis of Acidic and Alkaline Pretreatment Techniques for Bioethanol Production from Perennial Grasses

“…Perennial grasses, also known as native or herbaceous crops, stand out for their straightforward cultivation compared to annual crops; they offer advantages in terms of cost-effective cultivation, minimal water, fertilizer, and pesticide requirements, and adaptability to various climates, including marginal lands with poor soil quality, thus making them highly cost-effective [18][19][20][21][22]. Perennial grasses offer the potential to mitigate concerns related to land use, competition between food and fuel production, and other environmental threats compared to annual crops [23]. Moreover, at the end of their growth cycle, they exhibit impressively low moisture content and feature high cellulose content compared with other plant varieties [18].…”

“…Biotechnological methods have been used to explore perennial grasses for various applications, including bioethanol and biomethane production, as well as utilizing cellulose and hemicellulose for material synthesis [23]. Despite extensive research on different pretreatment techniques to enhance digestibility and fermentability, hydrolyzing perennial grasses and other lignocellulosic biomass into fermentable sugars remains a challenge because of LCB recalcitrance [24].…”

“…The objective of biomass pretreatment is to disrupt the compact and organized cell wall structure, making it more susceptible to enzymatic hydrolysis [23]. Scanning electron microscopy (SEM) analysis is commonly employed to visualize the effects of pretreatment on the cell wall structure of the biomass.…”

“…Morphological alterations in perennial grasses have been observed before and after acid and alkaline pretreatment in many studies [23,107,109]. The untreated biomass initially displays a compact structure, whereas the biomass subjected to pretreatment exhibits thinner and distorted fibers, indicating potential lignin removal or the formation of lignin-hemicellulose complexes.…”

CUTTING FREQUENCY IN CAYMAN GRASS (Urochloa HYBRID) ON THE CALORIFIC POWER OF THE MEXICAN WET TROPIC

“…On the other hand, it is important to consider that there are several factors that influence bioethanol production performance. For example, the type of pretreatment and its conditions, the presence of inhibitors that affect the growth and metabolic capacity of the microorganisms, the enzymatic saccharification yield, and the fermentative capacity of the microorganism to produce bioethanol (Souza-Rodrigues et al, 2021). Furthermore, the raw material used to obtain bioethanol is of utmost importance, since its origin, chemical composition, and even morphology will determine, to a large extent, the efficiency of pretreatment and saccharification, and therefore of fermentation (Brito et al, 2003).…”