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Second generation (2G) ethanol is produced through the use of lignocellulosic biomass. However, the pretreatment processes generates a variety of molecules (furan derivatives, phenolic compounds and organic acids) that act as inhibitors of microbial metabolism, and thus reduce the efficiency of the fermentation step in this process. In this context, the present study aimed to investigate the effect of furan derivatives on the physiology of lactic acid bacteria (LAB) strains that are potential contaminants of ethanol production. Homofermentative and heterofermentative strains of laboratory LAB and isolated from first generation ethanol fermentation were used. LAB strains were challenge to grow in the presence of furfural and hydroxymethyylfurfural (HMF). We found that the effect of HMF and furfural on the growth rate of LAB is dependent of the metabolic type, and growth kinetics in the presence of these compounds is enhanced for heterofermentative LAB, whereas is inhibitory to homofermentative LAB. Sugar consumption and product formation were also enhanced in the presence of furaldehydes in heterofermentative LAB, that displayed an effective detoxification kinetics when compared to the homofermentative LAB. This knowledge is important because LAB can be explored both within the scope of bio-detoxification, being applied before the fermentation.Key points‐Heterofermentative LAB presented the ability to decrease the concentrations of furfural and HMF‐LAB can be used in the bio-detoxification to remove the inhibitors before fermentations‐The presence of furan derivatives had a growth stimulus observed in heterofermentative LAB

O desenvolvimento de software para apoiar as ciências como uma nova plataforma de pesquisa e experimentação científica tem gerado contribuições para diversas áreas de conhecimento e é considerada tendência para os próximos anos. Neste artigo apresenta-se a plataforma +Precoce, voltada para o domínio da Pecuária que oferece modelos de sistemas de produção de gado de corte e permite que produtores rurais façam simulações considerando seus dados particulares. Os resultados obtidos mostram que a plataforma pode contribuir para a tomada de decisão no meio rural e gerar diversos benefícios, tais como a melhoria da qualidade da carne brasileira.

Second generation (2G) ethanol is produced using lignocellulosic biomass. However, the pre-treatment processes generate a variety of molecules (furan derivatives, phenolic compounds, and organic acids) that act as inhibitors of microbial metabolism, and thus reduce the efficiency of the fermentation step in this process. In this context, the present study aimed to investigate the effect of furan derivatives on the physiology of lactic acid bacteria (LAB) strains that are potential contaminants of ethanol production. Homofermentative and heterofermentative strains of laboratory LAB and isolated from first generation ethanol fermentation were used. LAB strains were challenged to grow in the presence of furfural and hydroxymethyylfurfural (HMF). We found that the effect of HMF and furfural on the growth rate of LAB is dependent of the metabolic type, and growth kinetics in the presence of these compounds is enhanced for heterofermentative LAB, whereas is inhibitory to homofermentative LAB. Sugar consumption and product formation were also enhanced in the presence of furaldehydes in heterofermentative LAB, that displayed effective detoxification kinetics when compared to the homofermentative LAB. This knowledge is important because lactic acid bacteria can be explored within the scope of bio-detoxification, as well as to guide metabolic engineering strategies to yeast biocatalysts based on the mechanisms used by these bacteria.

Production of second-generation ethanol from lignocellulosic residues should be fueling the energy matrix in the near future. Lignocellulosic feedstock has received much attention as an alternative energy resource for biorefineries toward reducing the demand for fossil resources, contributing to a future sustainable bio-based economy. Fermentation of lignocellulosic hydrolysates poses many scientific and technological challenges as the drawback of Saccharomyces cerevisiae's inability in fermenting pentose sugars (derived from hemicellulose). To overcome the inability of S. cerevisiae to ferment xylose and increase yeast robustness in the presence of inhibitory compound-containing media, the industrial S. cerevisiae strain SA-1 was engineered using CRISPR-Cas9 with the oxidoreductive xylose pathway from Scheffersomyces stipitis (encoded by XYL1, XYL2, and XYL3). The engineered strain was then cultivated in a xylose-limited chemostat under increasing dilution rates (for 64 days) to improve its xylose consumption kinetics under aerobic conditions. The evolved strain (DPY06) and its parental strain (SA-1 XR/XDH) were evaluated under anaerobic conditions in complex media. DPY06 consumed xylose faster, exhibiting an increase of 70% in xylose consumption rate at 72h of cultivation compared to its parental strain, indicating that laboratory evolution improved xylose uptake of SA-1 XR/XDH.

Production of second-generation ethanol from lignocellulosic residues should be fueling the energy matrix in the near future. Lignocellulosic feedstock has received much attention as an alternative energy resource for biorefineries toward reducing the demand for fossil resources, contributing to a future sustainable bio-based economy. Fermentation of lignocellulosic hydrolysates poses many scientific and technological challenges as the drawback of Saccharomyces cerevisiae’s inability in fermenting pentose sugars (derived from hemicellulose). To overcome the inability of S. cerevisiae to ferment xylose and increase yeast robustness in the presence of inhibitory compound-containing media, the industrial S. cerevisiae strain SA-1 was engineered using CRISPR-Cas9 with the oxidoreductive xylose pathway from Scheffersomyces stipitis (encoded by XYL1, XYL2, and XYL3). The engineered strain was then cultivated in a xylose-limited chemostat under increasing dilution rates (for 64 days) to improve its xylose consumption kinetics under aerobic conditions. The evolved strain (DPY06) and its parental strain (SA-1 XR/XDH) were evaluated under microaerobic in the hemicellulosic hydrolysate. DPY06 exhibited 35% superior volumetric ethanol productivity compared to its parental strain.

Purpose Second generation (2G) ethanol is produced using lignocellulosic biomass. However, the pre-treatment processes generate a variety of molecules (furan derivatives, phenolic compounds, and organic acids) that act as inhibitors of microbial metabolism, and thus reduce the efficiency of the fermentation step in this process. In this context, the present study aimed to investigate the effect of furan derivatives on the physiology of lactic acid bacteria (LAB) strains that are potential contaminants of ethanol production. Methodology: Homofermentative and heterofermentative strains of laboratory LAB and isolated from first generation ethanol fermentation were used. LAB strains were challenged to grow in the presence of furfural and hydroxymethyylfurfural (HMF). Results We found that the effect of HMF and furfural on the growth rate of LAB is dependent of the metabolic type, and growth kinetics in the presence of these compounds is enhanced for heterofermentative LAB, whereas is inhibitory to homofermentative LAB. Sugar consumption and product formation were also enhanced in the presence of furaldehydes in heterofermentative LAB, that displayed effective detoxification kinetics when compared to the homofermentative LAB. Conclusion This knowledge is important because lactic acid bacteria can be explored within the scope of bio-detoxification, as well as to guide metabolic engineering strategies to yeast biocatalysts based on the mechanisms used by these bacteria.

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