Deciphering layer formation in Red Heart Qu: A comprehensive study of metabolite profile and microbial community influenced by raw materials and environmental factors.

Environmental-origin microbiota significantly influences Red Heart Qu (RH_Qu) stratification, but their microbial migration and metabolic mechanisms remain unclear. Using high-throughput sequencing and metabolomics, we divided the stratification of RH_Qu into three temperature-based stages. Phase I features rising temperatures, causing microbial proliferation and a two-layer division.

Enhancing simultaneous saccharification and co-fermentation of corncob by Kluyveromyces marxianus through overexpression of putative transcription regulator.

Overexpression of a gene with unknown function in Kluyveromyces marxianus markedly improved tolerance to lignocellulosic biomass-derived inhibitors. This overexpression also enhanced tolerance to elevated temperatures, ethanol, and high concentrations of NaCl and glucose. Inhibitor degradation and transcriptome analyses related this K.

Unveiling malic acid biorefinery: Comprehensive insights into feedstocks, microbial strains, and metabolic pathways.

The over-reliance on fossil fuels and resultant environmental issues necessitate sustainable alternatives. Microbial fermentation of biomass for malic acid production offers a viable, eco-friendly solution, enhancing resource efficiency and minimizing ecological damage. This review covers three core aspects of malic acid biorefining: feedstocks, microbial strains, and metabolic pathways.

Structural Insights into the Catalytic Activity of -Acetylglucosamine Deacetylase.

-Acetylglucosamine deacetylase from (CmCBDA) is a highly effective and selective biocatalyst for the production of d-glucosamine (GlcN) from -acetylglucosamine (GlcNAc). However, the underlying catalytic mechanism remains elusive. Here, we show that CmCBDA is a metalloenzyme with a preference for Ni over Mn.

Effect of Caproicibacterium lactatifermentans inoculation on the microbial succession and flavor formation of pit mud used in Chinese Baijiu fermentation.

Caproicibacterium lactatifermentans is a major caproate-producing bacterium in high-quality pit mud and has an impact on the synthesis of fatty acids during Baijiu fermentation. To develop an effective method for cultivating high-quality pit mud, we explored the role of Caproicibacterium lactatifermentans inoculation. The inoculation resulted in a high level of Caproicibacterium lactatifermentans (29.

The novel properties of Kluyveromyces marxianus glucose sensor/receptor repressor pathway and the construction of glucose repression-released strains.

Background: Glucose repression in yeast leads to the sequential or diauxic utilization of mixed sugars and reduces the co-utilization of glucose and xylose from lignocellulosic biomasses. Study of the glucose sensing pathway helps to construct glucose repression-released yeast strains and enhance the utilization of lignocellulosic biomasses.

Results: Herein, the glucose sensor/receptor repressor (SRR) pathway of Kluyveromyces marxianus which mainly consisted of KmSnf3, KmGrr1, KmMth1, and KmRgt1 was studied.

Lignocellulosic xylitol production from corncob using engineered .

Xylitol production from lignocellulose hydrolysate is a sustainable and environment-friendly process. In this study, a systematic process of converting corncob waste into xylitol is described. First, the corncobs are hydrolyzed with acid to a hydrolysate.

Carotenoid production from nondetoxified xylose mother liquid or corncob hydrolysate with engineered Kluyveromyces marxianus.

Carotenoids are widely utilized in the food, pharmaceutical and nutraceutical industries. Here, Kluyveromyces marxianus was engineered to overproduce carotenoids from corncob hydrolysate or xylose mother liquid (XML, a byproduct of commercial xylose purification). First, the toxicity of fat-soluble carotenoids to cells was reduced by employing xylose inducible promoters using with a two-temperature strategy to separate cell growth and product accumulation.

Structural assembly of the nucleic-acid-binding Thp3-Csn12-Sem1 complex functioning in mRNA splicing.

PCI domain proteins play important roles in post-transcriptional gene regulation. In the TREX-2 complex, PCI domain-containing Sac3 and Thp1 proteins and accessory Sem1 protein form a ternary complex required for mRNA nuclear export. In contrast, structurally related Thp3-Csn12-Sem1 complex mediates pre-mRNA splicing.

Influence of prefoldin subunit 4 on the tolerance of Kluyveromyces marxianus to lignocellulosic biomass-derived inhibitors.

Background: Kluyveromyces marxianus is a potentially excellent host for microbial cell factories using lignocellulosic biomass, due to its thermotolerance, high growth rate, and wide substrate spectrum. However, its tolerance to inhibitors derived from lignocellulosic biomass pretreatment needs to be improved. The prefoldin complex assists the folding of cytoskeleton which relates to the stress tolerance, moreover, several subunits of prefoldin have been verified to be involved in gene expression regulation.

The development of a heterologous gene expression system in thermophilic fungus .

Unlabelled: is a thermophilic fungus that belongs to the ascomycetous class and has attracted increasing interest for its ability to produce thermostable cellulolytic enzymes and growth at elevated temperatures. However, studies on this organism have been limited because of the lack of a genetic manipulation system. Here, we developed a polyethylene glycol (PEG)-mediated transformation system for based on an orotidine-5'-monophosphate decarboxylase (pyrG)-deficient mutant, with this method achieving a transformation efficiency of 33 ± 3 transformants per microgram of DNA.

Efficiency enhancement of a new cellulase cocktail at low enzyme loading for high solid digestion of alkali catalyzed atmospheric glycerol organosolvent pre-treated sugarcane bagasse.

The acquisition during biomass saccharification of elevated levels of fermentable sugars with lower cellulase concentration is central to ensuring an economically viable and industrially relevant hydrolytic process. Thus, using a new cellulase preparation (LT4) at low cellulase loading (2 mg protein/g dried substrate), this study assessed the possible boosting effect of integrating accessory enzymes and additives on high-solids hydrolysis of sugarcane bagasse via fed-batch feeding. Hydrolysis which commenced with initial 8% solids loading and subsequent substrate feeding of 4% solids at 6 h, 18 h, and 24 h respectively, proved optimal for the 20% high-solids saccharification producing 158 g/L total sugars and 83% glucose yield after 72 h with the combined optimized additives and accessory enzymes.

Rapid Production of a Novel Al(III) Dependent Bioflocculant Isolated From 160-1 and Its Application Combined With Inorganic Salts.

An efficient bioflocculant-producing strain, 160-1, was identified by 16S rRNA and mass spectrometry analyses. Rapid production of bioflocculant EPS-160 was obtained with 10.01 g/(L⋅d) after optimized by response surface methodology.

Effect of a Novel Alpha/Beta Hydrolase Domain Protein on Tolerance of to Lignocellulosic Biomass Derived Inhibitors.

The multiple inhibitors tolerance of microorganism is important in bioconversion of lignocellulosic biomass which is a promising renewable and sustainable source for biofuels and other chemicals. The disruption of an unknown α/β hydrolase, which was termed KmYME and located in mitochondria in this study, resulted in the yeast more susceptible to lignocellulose-derived inhibitors, particularly to acetic acid, furfural and 5-HMF. The disrupted strain lost more mitochondrial membrane potential, showed increased plasma membrane permeability, severer redox ratio imbalance, and increased ROS accumulation, compared with those of the non-disrupted strain in the presence of the same inhibitors.

Release of glucose repression on xylose utilization in Kluyveromyces marxianus to enhance glucose-xylose co-utilization and xylitol production from corncob hydrolysate.

Background: Lignocellulosic biomass is one of the most abundant materials for biochemicals production. However, efficient co-utilization of glucose and xylose from the lignocellulosic biomass is a challenge due to the glucose repression in microorganisms. Kluyveromyces marxianus is a thermotolerant and efficient xylose-utilizing yeast.

Efficient l-lactic acid production from corncob residue using metabolically engineered thermo-tolerant yeast.

Lactic acid is an important industrial product and the production from inexpensive and renewable lignocellulose can reduce the cost and environmental pollution. In this study, a Kluyveromyces marxianus strain which produced lactic acid efficiently from corncob was constructed. Firstly, two of six different lactate dehydrogenases, which from Plasmodium falciparum and Bacillus subtilis, respectively, were proved to be effective for l-lactic acid production.

Efficient purification of a recombinant tag-free thermostable uricase by pH-induced self-cleavage of intein and expression in .

Uricase as an important healthcare-related protein is extensively used in the treatment of tumor lysis syndrome and in the manufacture of serum uric-acid diagnostic kits. In this study, a gene of a new thermostable uricase (KmUOX) was cloned from thermotolerant yeast . The uricase was fused with a self-cleaving intein and cellulose-binding affinity tag and expressed in BL21 (DE3).

Transcriptomic analysis of thermotolerant yeast in multiple inhibitors tolerance.

During pretreatment of lignocellulosic biomass, toxic compounds were released and inhibited the growth and fermentation of microorganisms. Here the global transcriptional response of to multiple inhibitors including acetic acid, phenols, furfural and HMF, at 42 °C, was studied, RNA-seq technology. Genes involved in the glycolysis pathway, fatty acid metabolism, ergosterol metabolism and vitamin B6 and B1 metabolic process were enriched in the down-regulated gene set, while genes involved in TCA cycle, respiratory chain, ROS detoxification and transporter coding genes were enriched in the up-regulated gene set in response to the multiple inhibitors stress.

High-fidelity de novo synthesis of pathways using microchip-synthesized oligonucleotides and general molecular biology equipment.

Engineering and evaluation of synthetic routes for generating valuable compounds require accurate and cost-effective de novo synthesis of genetic pathways. Here, we present an economical and streamlined de novo DNA synthesis approach for engineering a synthetic pathway with microchip-synthesized oligonucleotides (oligo). The process integrates entire oligo pool amplification, error-removal, and assembly of long DNA molecules.

Directed evolution to improve the catalytic efficiency of urate oxidase from Bacillus subtilis.

Urate oxidase is a key enzyme in purine metabolism and catalyzes the oxidation of uric acid to allantoin. It is used to treat hyperuricemia and gout, and also in a diagnostic kit. In this study, error-prone polymerase chain reaction and staggered extension process was used to generate a mutant urate oxidase with improved enzyme activity from Bacillus subtilis.

Identification of hexose kinase genes in Kluyveromyces marxianus and thermo-tolerant one step producing glucose-free fructose strain construction.

In yeast, the hexose assimilation is started at hexose phosphorylation. However, in Kluyveromyces marxianus, the hexokinase (HXK) and glucokinase (GLK) genes were not identified by experiments. Meanwhile, the glucose-free fructose product requires more cost-efficient method.

Metabolic engineering of indole pyruvic acid biosynthesis in Escherichia coli with tdiD.

Background: Indole pyruvic acid (IPA) is a versatile platform intermediate and building block for a number of high-value products in the pharmaceutical and food industries. It also has a wide range of applications, such as drugs for the nervous system, cosmetics, and luminophores. Chemical synthesis of IPA is a complicated and costly process.

Engineered Kluyveromyces marxianus for pyruvate production at elevated temperature with simultaneous consumption of xylose and glucose.

Xylose and glucose from lignocellulose are sustainable sources for production of pyruvate, which is the starting material for the synthesis of many drugs and agrochemicals. In this study, the pyruvate decarboxylase gene (KmPDC1) and glycerol-3-phosphate dehydrogenase gene (KmGPD1) of Kluyveromyces marxianus YZJ051 were disrupted to prevent ethanol and glycerol accumulation. The deficient growth of PDC disruption was rescued by overexpressing mutant KmMTH1-ΔT.

Recurring sequence-structure motifs in (βα)-barrel proteins and experimental optimization of a chimeric protein designed based on such motifs.

An interesting way of generating novel artificial proteins is to combine sequence motifs from natural proteins, mimicking the evolutionary path suggested by natural proteins comprising recurring motifs. We analyzed the βα and αβ modules of TIM barrel proteins by structure alignment-based sequence clustering. A number of preferred motifs were identified.

Immobilized MutS-Mediated Error Removal of Microchip-Synthesized DNA.

Applications of microchip-synthesized oligonucleotides for de novo gene synthesis are limited primarily by their high error rates. The mismatch binding protein MutS, which can specifically recognize and bind to mismatches, is one of the cheapest tools for error correction of synthetic DNA. Here, we describe a protocol for removing errors in microchip-synthesized oligonucleotides and for the assembly of DNA segments using these oligonucleotides.