Biosynthesis of nonnutritive monosaccharide d-allulose by metabolically engineered Escherichia coli from nutritive disaccharide sucrose.

Sucrose is a commonly utilized nutritive sweetener in food and beverages due to its abundance in nature and low production costs. However, excessive intake of sucrose increases the risk of metabolic disorders, including diabetes and obesity. Therefore, there is a growing demand for the development of nonnutritive sweeteners with almost no calories.

Engineering Escherichia coli for D-allulose biosynthesis from glycerol.

D-allulose, a naturally occurring monosaccharide, is present in small quantities in nature. It is considered a valuable low-calorie sweetener due to its low absorption in the digestive tract and zero energy for growth. Most of the recent efforts to produce D-allulose have focused on in vitro enzyme catalysis.

Enhanced Biosynthesis of d-Allulose from a d-Xylose-Methanol Mixture and Its Self-Inductive Detoxification by Using Antisense RNAs in .

d-Allulose, a C-3 epimer of d-fructose, has great market potential in food, healthcare, and medicine due to its excellent biochemical and physiological properties. Microbial fermentation for d-allulose production is being developed, which contributes to cost savings and environmental protection. A novel metabolic pathway for the biosynthesis of d-allulose from a d-xylose-methanol mixture has shown potential for industrial application.

Transporter mining and metabolic engineering of Escherichia coli for high-level D-allulose production from D-fructose by thermo-swing fermentation.

D-Allulose is an ultra-low-calorie sweetener with broad market prospects in the fields of food, beverage, health care, and medicine. The fermentative synthesis of D-allulose is still under development and considered as an ideal route to replace enzymatic approaches for large-scale production of D-allulose in the future. Generally, D-allulose is synthesized from D-fructose through Izumoring epimerization.

Conversion of acetate and glyoxylate to fumarate by a cell-free synthetic enzymatic biosystem.

Fumarate is a value-added chemical that is widely used in food, medicine, material, and agriculture industries. With the rising attention to the demand for fumarate and sustainable development, many novel alternative ways that can replace the traditional petrochemical routes emerged. The cell-free multi-enzyme catalysis is an effective method to produce high value chemicals.

Engineering as a novel chassis for PHB production from starch.

LHF01 was engineered to efficiently produce poly-3-hydroxybutyrate (PHB) from starch in this study. Firstly, the ability of LHF01 to directly accumulate PHB using soluble starch as the carbon source was explored, and the highest PHB titer of 2.06 g/L was obtained in 18 h shake flask cultivation.

Engineering of for D-allose fermentative synthesis from D-glucose through izumoring cascade epimerization.

D-Allose is a potential alternative to sucrose in the food industries and a useful additive for the healthcare products in the future. At present, the methods for large-scale production of D-allose are still under investigation, most of which are based on enzyme-catalyzed Izumoring epimerization. In contrast, fermentative synthesis of D-allose has never been reported, probably due to the absence of available natural microorganisms.

Methanol-Dependent Carbon Fixation for Irreversible Synthesis of d-Allulose from d-Xylose by Engineered .

d-Allulose is a rare hexose with great application potential, owing to its moderate sweetness, low energy, and unique physiological functions. The current strategies for d-allulose production, whether industrialized or under development, utilize six-carbon sugars such as d-glucose or d-fructose as a substrate and are usually based on the principle of reversible Izumoring epimerization. In this work, we designed a novel route that coupled the pathways of methanol reduction, pentose phosphate (PP), ribulose monophosphate (RuMP), and allulose monophosphate (AuMP) for to irreversibly synthesize d-allulose from d-xylose and methanol.

Metabolically Engineered for Conversion of D-Fructose to D-Allulose Phosphorylation-Dephosphorylation.

D-Allulose is an ultra-low calorie sweetener with broad market prospects. As an alternative to Izumoring, phosphorylation-dephosphorylation is a promising method for D-allulose synthesis due to its high conversion of substrate, which has been preliminarily attempted in enzymatic systems. However, phosphorylation-dephosphorylation requires polyphosphate as a phosphate donor and cannot completely deplete the substrate, which may limit its application in industry.

Intelligent self-control of carbon metabolic flux in SecY-engineered Escherichia coli for xylitol biosynthesis from xylose-glucose mixtures.

Xylitol is a salutary sugar substitute that has been widely used in the food, pharmaceutical, and chemical industries. Co-fermentation of xylose and glucose by metabolically engineered cell factories is a promising alternative to chemical hydrogenation of xylose for commercial production of xylitol. Here, we engineered a mutant of SecY protein-translocation channel (SecY [ΔP]) in xylitol-producing Escherichia coli JM109 (DE3) as a passageway for xylose uptake.

Engineering for d-Allulose Production from d-Fructose by Fermentation.

d-Allulose is considered an ideal alternative to sucrose and has shown tremendous application potential in many fields. Recently, most efforts on production of d-allulose have focused on enzyme-catalyzed epimerization of cheap hexoses. Here, we proposed an approach to efficiently produce d-allulose through fermentation using metabolically engineered JM109 (DE3), in which a SecY (ΔP) channel and a d-allulose 3-epimerase (DPEase) were co-expressed, ensuring that d-fructose could be transported in its nonphosphorylated form and then converted into d-allulose by cells.

Reprogramming of sugar transport pathways in Escherichia coli using a permeabilized SecY protein-translocation channel.

In the initial step of sugar metabolism, sugar-specific transporters play a decisive role in the passage of sugars through plasma membranes into cytoplasm. The SecY complex (SecYEG) in bacteria forms a membrane channel responsible for protein translocation. The present work shows that permeabilized SecY channels can be used as nonspecific sugar transporters in Escherichia coli.

Engineering and manipulation of a mevalonate pathway in Escherichia coli for isoprene production.

Isoprene is a useful phytochemical with high commercial values in many industrial applications including synthetic rubber, elastomers, isoprenoid medicines, and fossil fuel. Currently, isoprene is on large scale produced from petrochemical sources. An efficient biological process for isoprene production utilizing renewable feedstocks would be an important direction of research due to the fossil raw material depletion and air pollution.

Biosynthesis of D-glucaric acid from sucrose with routed carbon distribution in metabolically engineered Escherichia coli.

D-glucaric acid is a promising platform compound used to synthesize many other value-added or commodity chemicals. The engineering of Escherichia coli for efficiently converting D-glucose to D-glucaric acid has been attempted for several years, with mixed sugar fermentation recently gaining growing interests due to the increased D-glucaric acid yield. Here, we co-expressed cscB, cscA, cscK, ino1, miox, udh, and suhB in E.

Co-localization of proteins with defined sequential order and controlled stoichiometric ratio on magnetic nanoparticles.

Co-immobilization of enzymes used in cascade reactions is important for improving the overall catalytic efficiency. In this work, we employed scaffoldins as a bridge and succeeded in a highly-ordered co-localization of multiple proteins on magnetic nanoparticles with a loading capacity of ∼0.831 μmol g supports.

Engineered yeast with a CO-fixation pathway to improve the bio-ethanol production from xylose-mixed sugars.

Bio-ethanol production from lignocellulosic raw materials could serve as a sustainable potential for improving the supply of liquid fuels in face of the food-to-fuel competition and the growing energy demand. Xylose is the second abundant sugar of lignocelluloses hydrolysates, but its commercial-scale conversion to ethanol by fermentation is challenged by incomplete and inefficient utilization of xylose. Here, we use a coupled strategy of simultaneous maltose utilization and in-situ carbon dioxide (CO) fixation to achieve efficient xylose fermentation by the engineered Saccharomyces cerevisiae.

Engineering yeast with bifunctional minicellulosome and cellodextrin pathway for co-utilization of cellulose-mixed sugars.

Background: Consolidated bioprocessing (CBP), integrating cellulase production, cellulose saccharification, and fermentation into one step has been widely considered as the ultimate low-cost configuration for producing second-generation fuel ethanol. However, the requirement of a microbial strain able to hydrolyze cellulosic biomass and convert the resulting sugars into high-titer ethanol limits CBP application.

Results: In this work, cellulolytic yeasts were developed by engineering Saccharomyces cerevisiae with a heterologous cellodextrin utilization pathway and bifunctional minicellulosomes.

Site-Specific and High-Loading Immobilization of Proteins by Using Cohesin-Dockerin and CBM-Cellulose Interactions.

Immobilization of enzymes enhances their properties for application in industrial processes as reusable and robust biocatalysts. Here, we developed a new immobilization method by mimicking the natural cellulosome system. A group of cohesin and carbohydrate-binding module (CBM)-containing scaffoldins were genetically engineered, and their length was controlled by cohesin number.

Self-surface assembly of cellulosomes with two miniscaffoldins on Saccharomyces cerevisiae for cellulosic ethanol production.

Yeast to directly convert cellulose and, especially, the microcrystalline cellulose into bioethanol, was engineered through display of minicellulosomes on the cell surface of Saccharomyces cerevisiae. The construction and cell surface attachment of cellulosomes were accomplished with two individual miniscaffoldins to increase the display level. All of the cellulases including a celCCA (endoglucanase), a celCCE (cellobiohydrolase), and a Ccel_2454 (β-glucosidase) were cloned from Clostridium cellulolyticum, ensuring the thermal compatibility between cellulose hydrolysis and yeast fermentation.

Cell surface display of carbonic anhydrase on Escherichia coli using ice nucleation protein for COâ‚‚ sequestration.

Carbonic anhydrase (CA) has recently gained renewed interests for its potential as a mass-transfer facilitator for CO(2) sequestration. However, the low stability and high price severely limit its applications. In this work, the expression of α-CA from Helicobacter pylori on the outer membrane of Escherichia coli using a surface-anchoring system derived from ice nucleation protein (INP) from Pseudomonas syringae was developed.