Effective fermentation of sugarcane bagasse whole slurries using robust xylose-capable Saccharomyces cerevisiae

The pre-treatment of lignocellulose material toward cellulosic bioethanol production releases microbial inhibitors that severely limit the fermentation ability of Saccharomyces cerevisiae. This study evaluated to what degree robust xylose capable strains may improve the fermentability of non-detoxified sugarcane bagasse (SCB) slurries derived from steam explosion (StEX), and further compared this to slurries derived from ammonia fibre expansion (AFEX) pre-treatment. Initial screening in separate hydrolyses and co-fermentation processes using StEx-SCB hydrolysates identified S. cerevisiae TP-1 and CelluXTM4 with higher xylose consumption (≥ 88%) and ethanol concentrations (≥ 50 g/L). Subsequent fermentations compared StEx and AFEX pre-treated SCB material under industrially relevant fed-batch pre-hydrolysis simultaneous saccharification and co-fermentation (PSSCF) conditions, which resulted in only 3 g/L differences in ethanol titres for StEx and AFEX PSSCF fermentations. The study achieved non-detoxified whole-slurry co-fermentation using StEx pre-treated SCB, with higher ethanol yields than previously reported, by utilising robust xylose-capable strains.

Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations

The objective of this study is to enhance bio-butanol production using lignocellulosic feedstock via supplements of metabolism perturbation. Metabolic perturbations are non-substrate-based chemical additives that can reinforce metabolic flux towards butanol formation, or increase tolerance to microbial inhibitors in the feedstock. Typical metabolic perturbations include CaCO3, ZnSO4, methyl red, and furan derivatives such as furfural and hydroxymethylfurfural (HMF). In this study, we stepwise tailored metabolic perturbations to maximize butanol production from pure sugar and lignocellulosic feedstock. Under optimized conditions of 4 g/L CaCO3, 2 mg/L ZnSO4, butanol production exceeded 10g/L in wheat straw hydrolysate, which was significantly higher than that obtained in the absent of ZnSO4 and CaCO3. As compared to traditional lignocellulosic feedstock post-treatment method, metabolic perturbations method shows advantages in terms of productivity and economics. Improved bio-butanol production is related to the overexpression of NAD(P)H dependent genes.

Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations

The objective of this study is to enhance bio-butanol production using lignocellulosic feedstock via supplements of metabolism perturbation. Metabolic perturbations are non-substrate-based chemical additives that can reinforce metabolic flux towards butanol formation, or increase tolerance to microbial inhibitors in the feedstock. Typical metabolic perturbations include CaCO3, ZnSO4, methyl red, and furan derivatives such as furfural and hydroxymethylfurfural (HMF). In this study, we stepwise tailored metabolic perturbations to maximize butanol production from pure sugar and lignocellulosic feedstock. Under optimized conditions of 4 g/L CaCO3, 2 mg/L ZnSO4, butanol production exceeded 10g/L in wheat straw hydrolysate, which was significantly higher than that obtained in the absent of ZnSO4 and CaCO3. As compared to traditional lignocellulosic feedstock post-treatment method, metabolic perturbations method shows advantages in terms of productivity and economics. Improved bio-butanol production is related to the overexpression of NAD(P)H dependent genes.

SCREENING AND PRILIMINARY STUDY ON MICROBIAL STRAINS WITH INHIBITORY ACTIVITY AGAINST ENZYMES RELATING TO DIABETES IN VIETNAM

ABSTRACT – HCTN7Microorganisms are considered a rich and potential source for the bioactive guided exploitation of natural products. Commonly used enzyme inhibitors for diabetes treatment hitherto such as α-amylase and α-glucosidase inhibitors are mostly microbial sources derived. The present study was carried out with the aim of screening and questing microbial inhibitors against the most popular diabetes-related enzymes (α-amylase, α-glucosidase and PTP1B) in Vietnam. The investigation results revealed 19 of all 100 tested microbial crude extracts exhibiting inhibitory activity against at least one enzyme. Basing on morphological, physiological, biochemical, and rRNA 16/18S gene sequencing, the phylogeny of the most potent microbial strains was indentfied. The research results contributed confirming the potential of the research for natural compounds from microorganisms, and supported new materials for further studies to exploit medicinal active ingredients from microbial sources.