Pre-treatment step with Leuconostoc mesenteroides or L. pseudomesenteroides strains removes furfural from Zymomonas mobilis ethanolic fermentation broth

Leuconostoc pseudomesenteroides improves microbiota dysbiosis and liver metabolism imbalance and ameliorates the correlation between dihydroceramide and strains of Firmicutes and Proteobacteria in high fat diet obese mice

Leuconostoc pseudomesenteroides is widely isolated from fermented foods; however, the underlying molecular mechanism behind its anti-obesity function has rarely been studied. This study aims to explore the role of alterations in gut microbes and liver metabolites mediated by Leuconostoc pseudomesenteroides (Tu) in obese mice for a period of 8 weeks through UPLC/Q-TOF-MS and 16S rRNA sequencing. Our results showed that Tu administration at a dosage of 1 × 10⁹ CFU per day per mouse effectively attenuated the weight of mice, significantly reduced serum lipids, and markedly improved fecal lipid output. Tu also ameliorated the lipid profiles in the liver and epididymal fat tissues, and restored intestinal disorder caused by a high-fat diet. Moreover, glycerophospholipid metabolism in the liver was altered by increased dihydroceramide levels. Surprisingly, the correlation between dihydroceramide and strains of Firmicutes and Proteobacteria was found for the first time. Collectively, these findings highlight that Tu could be a potential dietary supplement for weight control.

Acceleration of biodetoxification on dilute acid pretreated lignocellulose feedstock by aeration and the consequent ethanol fermentation evaluation

BACKGROUND

Biodetoxification by the fungus Amorphotheca resinae ZN1 provides an effective way of inhibitor removal from pretreated lignocellulose feedstock and has been applied in the process of ethanol, biolipids, and lactic acid production. However, the long-time used and the consumption of considerable xylose in the pretreated materials reduced the process efficiency. The improvements of biodetoxification should be made to enhance the production of biochemical from lignocellulosic materials.

RESULTS

This study reported an acceleration method of A. resinae ZN1-based biodetoxification on the corn stover (CS) feedstock pretreated using dry dilute acid pretreatment. Under proper aeration and well-mixing condition, the conversion rate of furfural, 5-hydroxymethylfurfural (HMF), acetic acid, and typical phenolic compounds were significantly accelerated by more than twofolds faster, which resulted in the reduction of biodetoxification time from 96 h in the conventional process to 36 h. Simultaneous saccharification and ethanol fermentation assay on accelerated biodetoxification of the dry dilute acid pretreated CS feedstock achieved the similar ethanol titer (48.56 g/L of 36 h' accelerated biodetoxification vs. 50.00 g/L of 4 days' conventional biodetoxification) and yield (58.10 vs. 59.63 %). Substrate priority of inhibitors to sugars by A. resinae ZN1 was discovered and considerable xylose was reserved in the accelerated biodetoxification. Cell growth of A. resinae fungus in liquid medium and on pretreated CS solids revealed that the enhanced aeration enhanced the biodetoxification rate rather than the cell growth rate. Accelerated inhibitor conversion might come from the increased supply of cofactors of nicotinamide adenine dinucleotide or nicotinamide adenine dinucleotide phosphate from the step of aldehyde inhibitors to the corresponding acids, instead of cell mass increase.

CONCLUSION

Accelerated biodetoxification reduced the period of biodetoxification and retained the xylose components in the pretreated CS, which provided a practical method on improving process efficiency for cellulosic ethanol production from severe pretreated lignocellulose feedstock.