2G ethanol from the whole sugarcane lignocellulosic biomass

Abstract

BackgroundIn the sugarcane industry, large amounts of lignocellulosic residues are generated, which includes bagasse, straw, and tops. The use of the whole sugarcane lignocellulosic biomass for the production of second-generation (2G) ethanol can be a potential alternative to contribute to the economic viability of this process. Here, we conducted a systematic comparative study of the use of the lignocellulosic residues from the whole sugarcane lignocellulosic biomass (bagasse, straw, and tops) from commercial sugarcane varieties for the production of 2G ethanol. In addition, the feasibility of using a mixture of these residues from a selected variety was also investigated.ResultsThe materials were pretreated with dilute acid and hydrolyzed with a commercial enzymatic preparation, after which the hydrolysates were fermented using an industrial strain of Saccharomyces cerevisiae. The susceptibility to enzymatic saccharification was higher for the tops, followed by straw and bagasse. Interestingly, the fermentability of the hydrolysates showed a different profile, with straw achieving the highest ethanol yields, followed by tops and bagasse. Using a mixture of the different sugarcane parts (bagasse-straw-tops, 1:1:1, in a dry-weight basis), it was possible to achieve a 55% higher enzymatic conversion and a 25% higher ethanol yield, compared to use of the bagasse alone. For the four commercial sugarcane varieties evaluated using the same experimental set of conditions, it was found that the variety of sugarcane was not a significant factor in the 2G ethanol production process.ConclusionsAssessment of use of the whole lignocellulosic sugarcane biomass clearly showed that 2G ethanol production could be significantly improved by the combined use of bagasse, straw, and tops, when compared to the use of bagasse alone. The lower susceptibility to saccharification of sugarcane bagasse, as well as the lower fermentability of its hydrolysates, can be compensated by using it in combination with straw and tops (sugarcane trash). Furthermore, given that the variety was not a significant factor for the 2G ethanol production process within the four commercial sugarcane varieties evaluated here, agronomic features such as higher productivity and tolerance of soil and climate variations can be used as the criteria for variety selection.

High-Throughput Profiling of the Fiber and Sugar Composition of Sugarcane Biomass

“…The use of low-lignin, highfiber biomass sources are preferred in biofuel production, not only to reduce the cost of pretreatment but also to gain higher sugar yield [59]. Typical lignin content reported for some lignocellulosic biomass sources are as follows: eucalypts (27.5-32.7 %) [60], poplar (21-29 %) reviewed in [61], and sugarcane (19.1-31.4 % for extractives-free bagasse reviewed in [28], 13.2 % dry biomass basis in [62]). Our data reported lignin content ranging 12-20 % on a pressed fiber dry mass basis, 2-4 % of total fresh biomass, and 6-14 % of total dry biomass.…”

Enhanced Endoglucanase Production by Bacillus aerius on Mixed Lignocellulosic Substrates

“…Studies on other applications of lignocellulosic mixtures have demonstrated that combining substrates usually has no negative impacts on product yields; more often than not, higher yields were obtained on mixtures than on the single substrates. Such observations have been reported with respect to the pretreatment and hydrolysis of mixed substrates (Jensen et al 2008;Moutta et al 2013;Moutta et al 2014;Pereira et al 2015), bioethanol production (Erdei et al 2010;Pereira et al 2015), and fungal cellulase production (Olsson et al 2003). …”

Otimização de parâmetros operacionais do pré-tratamento da palha de cana-de-açúcar

“…As condições climáticas existentes no país são, portanto, bastante favoráveis para a obtenção de energia a partir das biomassas [4]. Outro fator que corrobora essa afirmação é o fato do Brasil ter sido pioneiro na produção de etanol a partir da cana-de-açúcar (denominado de etanol de primeira geração, E1G).…”