Influence of reactors, microbial carbohydrate uptake, and metabolic pathways on ethanol production from grass biomass: A review

Abstract

Summary Grasses are considered to be potential lignocellulosic feedstock for renewable and sustainable biofuels such as bioethanol. However, the process involved, ie, pretreatment, enzymatic saccharification, and fermentation in conversion of these lignocellulosic biomass to bioethanol, remains expensive and at present is not affordable for industrial production. Thus, the present review assesses the influence of the recent technologies that can be employed for the bio‐refinery based pretreatment and enzymatic hydrolysis of grass biomass using advanced bioreactors. Since plant extracts have been seen to enhance the glucose uptake, an experiment was implemented to elucidate the role of plant extracts (bark extracts of Xylocarpus granatum) on glucose uptake capacity of microorganisms like Saccharomyces cerevisiae, Pichia sp., and Zymomonas mobilis and their subsequent ethanol production capability from glucose and xylose sugars. The results of these experiments indicated that supplementation of plant extracts promoted both glucose and xylose uptake in S. cerevisiae and Pichia sp. as compared with the control and Z. mobilis strain. Further, as Pichia sp. exhibited good uptake ability for both glucose and xylose, a model was proposed focusing on the gene silencing and operon concept in Pichia sp. for preferential pentose utilization during the fermentation of grass biomass to bioethanol.

Tannin-Tolerant Saccharomyces cerevisiae Isolated from Traditional Fermented Tea Leaf (Miang) and Application in Fruit Wine Fermentation Using Longan Juice Mixed with Seed Extract as Substrate

“…On the other hand, the addition of 1% TA significantly reduced fermentation efficiency for all strains (B5-1: 74.81%, B5-2: 83.79%, C6-3: 84.39%, and SC-5088: 83.75%), with efficiency remaining in the range of 54.03% to 49.92% when using isolated strains B5-2 and C6-3. These findings indicate that tannins interfere with yeast metabolism and ethanol production through multiple mechanisms, including exerting toxic effects on yeast cells, chelating essential metal ions, disrupting sugar uptake, and ultimately reducing the efficiency of the fermentation process [38,39]. The extent of these effects varies depending on the concentration of tannins in the The efficacy and productivity of ethanol production by four S. cerevisiae strains (B5-1, B5-2, C6-3, and SC-5088) were evaluated for their glucose consumption and ethanol production abilities with varying TA concentrations.…”

Identifying carbohydrate-active enzymes of Cutaneotrichosporon oleaginosus using systems biology

“…In addition, the intracellular processing of these mobilised carbohydrates by specific enzymes is required for their metabolic utilisation. Although the metabolic routes for carbohydrate uptake and consumption have been described for model yeasts such as S. cerevisiae and Pichia pastoris, no equivalent data are available for C. oleaginosus [19][20][21].…”