One-pot synthesis of cellobiose from sucrose using sucrose phosphorylase and cellobiose phosphorylase co-displaying Pichia pastoris as a reusable whole-cell biocatalyst.

Cellobiose has received increasing attention in various industrial sectors, ranging from food and feed to cosmetics. The development of large-scale cellobiose applications requires a cost-effective production technology as currently used methods based on cellulose hydrolysis are costly. Here, a one-pot synthesis of cellobiose from sucrose was conducted using a recombinant Pichia pastoris strain as a reusable whole-cell biocatalyst.

Sulfated and non-sulfated chondroitin affect the composition and metabolism of human colonic microbiota simulated in an in vitro fermentation system.

Chondroitin sulfate (CS) is a family of glycosaminoglycans and have a wide range of applications in dietary supplements and pharmaceutical drugs. In this study, we evaluated the effects of several types of CS, differing in their sulfated positions, on the human colonic microbiota and their metabolites. CS (CSA, CSC, and CSE) and non-sulfated chondroitin (CH) were added into an in vitro human colonic microbiota model with fecal samples from 10 healthy individuals.

Direct production of 4-hydroxybenzoic acid from cellulose using cellulase-displaying Pichia pastoris.

4-hydroxybenzoic acid (4-HBA) is an industrially important aromatic compound, and there is an urgent need to establish a bioprocess to produce this compound in a sustainable and environmentally friendly manner from renewable feedstocks such as cellulosic biomass. Here, we developed a bioprocess to directly produce 4-HBA from cellulose using a recombinant Pichia pastoris strain that displays heterologous cellulolytic enzymes on its cell surface via the glycosylphosphatidylinositol (GPI)-anchoring system. β-glucosidase (BGL) from Aspergillus aculeatus, endoglucanase (EG) from Trichoderma reesei, and cellobiohydrolase (CBH) from Talaromyces emersonii were co-displayed on the cell surface of P.

Enhanced production of 3,4-dihydroxybutyrate from xylose by engineered yeast via xylonate re-assimilation under alkaline condition.

To realize lignocellulose-based bioeconomy, efficient conversion of xylose into valuable chemicals by microbes is necessary. Xylose oxidative pathways that oxidize xylose into xylonate can be more advantageous than conventional xylose assimilation pathways because of fewer reaction steps without loss of carbon and ATP. Moreover, commodity chemicals like 3,4-dihydroxybutyrate and 3-hydroxybutyrolactone can be produced from the intermediates of xylose oxidative pathway.

Improvement of cell-tethered cellulase activity in recombinant strains of Saccharomyces cerevisiae.

Consolidated bioprocessing (CBP) remains an attractive option for the production of commodity products from pretreated lignocellulose if a process-suitable organism can be engineered. The yeast Saccharomyces cerevisiae requires engineered cellulolytic activity to enable its use in CBP production of second-generation (2G) bioethanol. A promising strategy for heterologous cellulase production in yeast entails displaying enzymes on the cell surface by means of glycosylphosphatidylinositol (GPI) anchors.

Construction of an l-Tyrosine Chassis in Enhances Aromatic Secondary Metabolite Production from Glycerol.

Bioactive plant-based secondary metabolites such as stilbenoids, flavonoids, and benzylisoquinoline alkaloids (BIAs) are produced from l-tyrosine (l-Tyr) and have a wide variety of commercial applications. Therefore, building a microorganism with high l-Tyr productivity (l-Tyr chassis) is of immense value for large-scale production of various aromatic compounds. The aim of this study was to develop an l-Tyr chassis in the nonconventional yeast () to produce various aromatic secondary metabolites (resveratrol, naringenin, norcoclaurine, and reticuline).

Resveratrol production from several types of saccharide sources by a recombinant strain.

Resveratrol is a plant-derived aromatic compound with a wide range of beneficial properties including antioxidant and anti-aging effects. The resveratrol currently available on the market is predominantly extracted from certain plants such as grape and the Japanese knotweed . Due to the unstable harvest of these plants and the low resveratrol purity obtained, it is necessary to develop a stable production process of high-purity resveratrol from inexpensive feedstocks.

Resveratrol production of a recombinant strain from molasses.

Resveratrol is a plant-derived aromatic compound with beneficial properties and it is required to develop a resveratrol production process from inexpensive biomass feedstocks. Here, we investigated the potential of , a non-conventional yeast with the capacity to utilize a wide range of sugars, to produce resveratrol from molasses, which is a by-product of sugar refineries. The strain metabolically engineered for resveratrol production produced resveratrol from 60 g/L mixed sugar (sucrose, glucose, and fructose), while its resveratrol titer decreased as the proportions of glucose and fructose increased.

Pretreatment of extruded Napier grass byhydrothermal process with dilute sulfuric acid and fermentation using a cellulose-hydrolyzing and xylose-assimilating yeast for ethanol production.

One of the potential bioresources for bioethanol production is Napier grass, considering its high cellulose and hemicellulose content. However, the cost of pretreatment hinders the bioethanol produced from being economical. This study examines the effect of hydrothermal process with dilute acid on extruded Napier grass, followed by enzymatic saccharification prior to simultaneous saccharification and co-fermentation (SScF).

Improving the functionality of surface-engineered yeast cells by altering the cell wall morphology of the host strain.

The expression of functional proteins on the cell surface using glycosylphosphatidylinositol (GPI)-anchoring technology is a promising approach for constructing yeast cells with special functions. The functionality of surface-engineered yeast strains strongly depends on the amount of functional proteins displayed on their cell surface. On the other hand, since the yeast cell wall space is finite, heterologous protein carrying capacity of the cell wall is limited.

Enhancing carbohydrate repartitioning into lipid and carotenoid by disruption of microalgae starch debranching enzyme.

Light/dark cycling is an inherent condition of outdoor microalgae cultivation, but is often unfavorable for lipid accumulation. This study aims to identify promising targets for metabolic engineering of improved lipid accumulation under outdoor conditions. Consequently, the lipid-rich mutant Chlamydomonas sp.

Novel strategy for anchorage position control of GPI-attached proteins in the yeast cell wall using different GPI-anchoring domains.

The yeast cell surface provides space to display functional proteins. Heterologous proteins can be covalently anchored to the yeast cell wall by fusing them with the anchoring domain of glycosylphosphatidylinositol (GPI)-anchored cell wall proteins (GPI-CWPs). In the yeast cell-surface display system, the anchorage position of the target protein in the cell wall is an important factor that maximizes the capabilities of engineered yeast cells because the yeast cell wall consists of a 100- to 200-nm-thick microfibrillar array of glucan chains.

Production of 1,2,4-butanetriol from xylose by Saccharomyces cerevisiae through Fe metabolic engineering.

1,2,4-Butanetriol can be used to produce energetic plasticizer as well as several pharmaceutical compounds. Although Saccharomyces cerevisiae has some attractive characters such as high robustness for industrial production of useful chemicals by fermentation, 1,2,4-butanetriol production by S. cerevisiae has not been reported.

Combined Cell Surface Display of β-d-Glucosidase (BGL), Maltose Transporter (MAL11), and Overexpression of Cytosolic Xylose Reductase (XR) in Saccharomyces cerevisiae Enhance Cellobiose/Xylose Coutilization for Xylitol Bioproduction from Lignocellulosic Biomass.

Xylitol is a highly valuable commodity chemical used extensively in the food and pharmaceutical industries. The production of xylitol from d-xylose involves a costly and polluting catalytic hydrogenation process. Biotechnological production from lignocellulosic biomass by micro-organisms like yeasts is a promising option.

Widespread effect of N-acetyl-D-glucosamine assimilation on the metabolisms of amino acids, purines, and pyrimidines in Scheffersomyces stipitis.

Background: Following cellulose, chitin is the most abundant renewable resource and is composed of the monomeric amino sugar N-acetyl-D-glucosamine (GlcNAc). Although many yeasts, including Saccharomyces cerevisiae, have lost their ability to utilize GlcNAc, some yeasts are able to use GlcNAc as a carbon source. However, our understanding of the effects of GlcNAc on the intracellular metabolism of nitrogen-containing compounds in these yeast species is limited.

Direct and highly productive conversion of cyanobacteria to ethanol with CaCl addition.

Background: The cyanobacterium shows promise as a carbohydrate feedstock for biofuel production. The glycogen accumulated in can be extracted by lysozyme-degrading the peptidoglycan layer of the bacterial cell walls. The extracted glycogen can be converted to ethanol through hydrolysis by amylolytic enzymes and fermentation by the yeast .

Improvement of Xylose Fermentation Ability under Heat and Acid Co-Stress in Using Genome Shuffling Technique.

Xylose-assimilating yeasts with tolerance to both fermentation inhibitors (such as weak organic acids) and high temperature are required for cost-effective simultaneous saccharification and cofermentation (SSCF) of lignocellulosic materials. Here, we demonstrate the construction of a novel xylose-utilizing strain with improved fermentation ability under heat and acid co-stress using the drug resistance marker-aided genome shuffling technique. The mutagenized genome pools derived from xylose-utilizing diploid yeasts with thermotolerance or acid tolerance were shuffled by sporulation and mating.

Enhanced cell-surface display of a heterologous protein using SED1 anchoring system in SED1-disrupted Saccharomyces cerevisiae strain.

Yeast displaying enzymes on the cell surface are used for developing whole-cell biocatalysts. High enzyme activity on the cell surface is required in certain applications such as direct ethanol production from lignocellulosic materials. However, the cell surface enzyme activity is limited by several factors, one of which is the protein amount of the yeast cell wall.

Improvement of ethanol production from crystalline cellulose via optimizing cellulase ratios in cellulolytic Saccharomyces cerevisiae.

Crystalline cellulose is one of the major contributors to the recalcitrance of lignocellulose to degradation, necessitating high dosages of cellulase to digest, thereby impeding the economic feasibility of cellulosic biofuels. Several recombinant cellulolytic yeast strains have been developed to reduce the cost of enzyme addition, but few of these strains are able to efficiently degrade crystalline cellulose due to their low cellulolytic activities. Here, by combining the cellulase ratio optimization with a novel screening strategy, we successfully improved the cellulolytic activity of a Saccharomyces cerevisiae strain displaying four different synergistic cellulases on the cell surface.

Mapping of endoglucanases displayed on yeast cell surface using atomic force microscopy.

The surface of yeast cells has been an attractive interface for the effective use of cellulose. Surface enzymes, however, are difficult to visualize and evaluate. In this study, two kinds of unique anchoring regions were used to display the cellulase, endoglucanase (EG), on a yeast cell surface.

Ethanol production from N-acetyl-D-glucosamine by Scheffersomyces stipitis strains.

N-acetyl-D-glucosamine (GlcNAc) is the building block of chitin, which is one of the most abundant renewable resources in nature after cellulose. Therefore, a microorganism that can utilize GlcNAc is necessary for chitin-based biorefinery. In this study, we report on the screening and characterization of yeast strains for bioethanol production from GlcNAc.

Enhanced cell-surface display and secretory production of cellulolytic enzymes with Saccharomyces cerevisiae Sed1 signal peptide.

Recombinant yeast strains displaying aheterologous cellulolytic enzymes on their cell surfaces using a glycosylphosphatidylinositol (GPI) anchoring system are a promising strategy for bioethanol production from lignocellulosic materials. A crucial step for cell wall localization of the enzymes is the intracellular transport of proteins in yeast cells. Therefore, the addition of a highly efficient secretion signal sequence is important to increase the amount of the enzymes on the yeast cell surface.

Engineering of a novel cellulose-adherent cellulolytic Saccharomyces cerevisiae for cellulosic biofuel production.

Cellulosic biofuel is the subject of increasing attention. The main obstacle toward its economic feasibility is the recalcitrance of lignocellulose requiring large amount of enzyme to break. Several engineered yeast strains have been developed with cellulolytic activities to reduce the need for enzyme addition, but exhibiting limited effect.