-
World Journal of Microbiology &... Jun 2022Interest in the production of renewable chemicals from biomass has increased in the past years. Among these chemicals, carboxylic acids represent a significant part of... (Review)
Review
Interest in the production of renewable chemicals from biomass has increased in the past years. Among these chemicals, carboxylic acids represent a significant part of the most desirable bio-based products. Xylonic acid is a five-carbon sugar-acid obtained from xylose oxidation that can be used in several industrial applications, including food, pharmaceutical, and construction industries. So far, the production of xylonic acid has not yet been available at an industrial scale; however, several microbial bio-based production processes are under development. This review summarizes the recent advances in pathway characterization, genetic engineering, and fermentative strategies to improve xylonic acid production by microorganisms from xylose or lignocellulosic hydrolysates. In addition, the strengths of the available microbial strains and processes and the major requirements for achieving biotechnological production of xylonic acid at a commercial scale are discussed. Efficient native and engineered microbial strains have been reported. Xylonic acid titers as high as 586 and 171 g L were obtained from bacterial and yeast strains, respectively, in a laboratory medium. Furthermore, relevant academic and industrial players associated with xylonic acid production will be presented.
Topics: Biomass; Biotechnology; Fermentation; Metabolic Engineering; Xylose
PubMed: 35668329
DOI: 10.1007/s11274-022-03313-5 -
Biomolecules May 2021The pentose phosphate pathway (PPP) is a route that can work in parallel to glycolysis in glucose degradation in most living cells. It has a unidirectional oxidative... (Review)
Review
The pentose phosphate pathway (PPP) is a route that can work in parallel to glycolysis in glucose degradation in most living cells. It has a unidirectional oxidative part with glucose-6-phosphate dehydrogenase as a key enzyme generating NADPH, and a non-oxidative part involving the reversible transketolase and transaldolase reactions, which interchange PPP metabolites with glycolysis. While the oxidative branch is vital to cope with oxidative stress, the non-oxidative branch provides precursors for the synthesis of nucleic, fatty and aromatic amino acids. For glucose catabolism in the baker's yeast , where its components were first discovered and extensively studied, the PPP plays only a minor role. In contrast, PPP and glycolysis contribute almost equally to glucose degradation in other yeasts. We here summarize the data available for the PPP enzymes focusing on and , and describe the phenotypes of gene deletions and the benefits of their overproduction and modification. Reference to other yeasts and to the importance of the PPP in their biotechnological and medical applications is briefly being included. We propose future studies on the PPP in to be of special interest for basic science and as a host for the expression of human disease genes.
Topics: Animals; Glucose; Glycolysis; Humans; Kluyveromyces; Oxidation-Reduction; Oxidative Stress; Pentose Phosphate Pathway; Saccharomyces cerevisiae; Xylose
PubMed: 34065948
DOI: 10.3390/biom11050725 -
Journal of Industrial Microbiology &... Jan 2015Lignocellulosic substrates are the largest source of fermentable sugars for bioconversion to fuel ethanol and other valuable compounds. To improve the economics of... (Review)
Review
Lignocellulosic substrates are the largest source of fermentable sugars for bioconversion to fuel ethanol and other valuable compounds. To improve the economics of biomass conversion, it is essential that all sugars in potential hydrolysates be converted efficiently into the desired product(s). While hexoses are fermented into ethanol and some high-value chemicals, the bioconversion of pentoses in hydrolysates remains inefficient. This remains one of the key challenges in lignocellulosic biomass conversion. Native pentose-fermenting yeasts can ferment both glucose and xylose in lignocellulosic biomass to ethanol. However, they perform poorly in the presence of hydrolysate inhibitors, exhibit low ethanol tolerance and glucose repression, and ferment pentoses less efficiently than the main hexoses glucose and mannose. This paper reviews classical and molecular strain improvement strategies applied to native pentose-fermenting yeasts for improved ethanol production from xylose and lignocellulosic substrates. We focus on Pachysolen tannophilus, Scheffersomyces (Candida) shehatae, Scheffersomyces (Pichia) stipitis, and Spathaspora passalidarum which are good ethanol producers among the native xylose-fermenting yeasts. Strains obtained thus far are not robust enough for efficient ethanol production from lignocellulosic hydrolysates and can benefit from further improvements.
Topics: Biofuels; Biomass; Candida; DNA, Fungal; Ethanol; Fermentation; Glucose; Pentoses; Pichia; Saccharomycetales; Xylose; Yeasts
PubMed: 25404205
DOI: 10.1007/s10295-014-1535-z -
International Journal of Biological... Jan 2021L-Fuculose and D-ribulose are kinds of rare sugars used in food, agriculture, and medicine industries. These are pentoses and categorized into the two main groups, aldo... (Review)
Review
L-Fuculose and D-ribulose are kinds of rare sugars used in food, agriculture, and medicine industries. These are pentoses and categorized into the two main groups, aldo pentoses and ketopentoses. There are 8 aldo- and 4 ketopentoses and only fewer are natural, while others are rare sugars found in a very small amount in nature. These sugars have great commercial applications, especially in many kinds of drugs in the medicine industry. The synthesis of these sugars is very expensive, difficult by chemical methods due to its absence in nature, and could not meet industry demands. The pentose izumoring strategy offers a complete enzymatic tactic to link all kinds of pentoses using different enzymes. The enzymatic production of L-fuculose and D-ribulose through L-fucose isomerase (L-FI) and D-arabinose isomerase (D-AI) is the inexpensive and uncomplicated method up till now. Both enzymes have similar kinds of isomerizing mechanisms and each enzyme can catalyze both L-fucose and D-arabinose. In this review article, the enzymatic process of biochemically characterized L-FI & D-AI, their application to produce L-fuculose and D-ribulose and its uses in food, agriculture, and medicine industries are reviewed.
Topics: Agriculture; Aldose-Ketose Isomerases; Food Industry; Hexoses; Pentoses; Substrate Specificity
PubMed: 33296692
DOI: 10.1016/j.ijbiomac.2020.12.021 -
Communications Biology Nov 2022Bacteria and Eucarya utilize the non-oxidative pentose phosphate pathway to direct the ribose moieties of nucleosides to central carbon metabolism. Many archaea do not...
Bacteria and Eucarya utilize the non-oxidative pentose phosphate pathway to direct the ribose moieties of nucleosides to central carbon metabolism. Many archaea do not possess this pathway, and instead, Thermococcales utilize a pentose bisphosphate pathway involving ribose-1,5-bisphosphate (R15P) isomerase and ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco). Intriguingly, multiple genomes from halophilic archaea seem only to harbor R15P isomerase, and do not harbor Rubisco. In this study, we identify a previously unrecognized nucleoside degradation pathway in halophilic archaea, composed of guanosine phosphorylase, ATP-dependent ribose-1-phosphate kinase, R15P isomerase, RuBP phosphatase, ribulose-1-phosphate aldolase, and glycolaldehyde reductase. The pathway converts the ribose moiety of guanosine to dihydroxyacetone phosphate and ethylene glycol. Although the metabolic route from guanosine to RuBP via R15P is similar to that of the pentose bisphosphate pathway in Thermococcales, the downstream route does not utilize Rubisco and is unique to halophilic archaea.
Topics: Ribulose-Bisphosphate Carboxylase; Ribose; Pentoses; Archaea; Guanosine; Phosphates
PubMed: 36434094
DOI: 10.1038/s42003-022-04247-2 -
Applied Microbiology and Biotechnology Jul 2020Currently, due to the special functions and potential application values, rare sugars become the hot topic in carbohydrate fields. L-Ribulose, an isomer of L-ribose, is... (Review)
Review
Currently, due to the special functions and potential application values, rare sugars become the hot topic in carbohydrate fields. L-Ribulose, an isomer of L-ribose, is an expensive rare ketopentose. As an important precursor for other rare sugars and L-nucleoside analogue synthesis, L-ribulose attracts more and more attention in recent days. Compared with complicated chemical synthesis, the bioconversion method becomes a good alternative approach to L-ribulose production. Generally, the bioconversion of L-ribulose was linked with ribitol, L-arabinose, L-ribose, L-xylulose, and L-arabitol. Herein, an overview of recent advances in the metabolic pathway, chemical synthesis, bioproduction of L-ribulose, and the potential application of L-ribulose is reviewed in detail in this paper. KEY POINTS: 1. L-Ribulose is a rare sugar and the key precursor for L-ribose production. 2. L-Ribulose is the starting material for L-nucleoside derivative synthesis. 3. Chemical synthesis, bioproduction, and applications of L-ribulose are reviewed.
Topics: Arabinose; Bacteria; Bacterial Proteins; Biocatalysis; Biotransformation; Metabolic Networks and Pathways; Pentoses; Ribitol; Ribose; Sugar Alcohols; Xylulose
PubMed: 32372201
DOI: 10.1007/s00253-020-10637-5 -
Proceedings of the National Academy of... Apr 2024Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the...
Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the product of the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been presumed that the occurrence of 2-phosphoglycolate salvage is linked to the CBB cycle, and in particular, the C2 pathway to the CBB cycle and oxygenic photosynthesis. Here, we examined 2-phosphoglycolate salvage in the hyperthermophilic archaeon , an obligate anaerobe that harbors a Rubisco that functions in the pentose bisphosphate pathway. harbors enzymes that have the potential to convert 2-phosphoglycolate to glycine and serine, and their genes were identified by biochemical and/or genetic analyses. 2-phosphoglycolate phosphatase activity increased 1.6-fold when cells were grown under microaerobic conditions compared to anaerobic conditions. Among two candidates, TK1734 encoded a phosphatase specific for 2-phosphoglycolate, and the enzyme was responsible for 80% of the 2-phosphoglycolate phosphatase activity in cells. The TK1734 disruption strain displayed growth impairment under microaerobic conditions, which was relieved upon addition of sodium sulfide. In addition, glycolate was detected in the medium when was grown under microaerobic conditions. The results suggest that removes 2-phosphoglycolate via a phosphatase reaction followed by secretion of glycolate to the medium. As the Rubisco in functions in the pentose bisphosphate pathway and not in the CBB cycle, mechanisms to remove 2-phosphoglycolate in this archaeon emerged independent of the CBB cycle.
Topics: Ribulose-Bisphosphate Carboxylase; Archaea; Photosynthesis; Glycolates; Phosphoric Monoester Hydrolases; Oxygenases; Pentoses
PubMed: 38593075
DOI: 10.1073/pnas.2311390121 -
Applied Microbiology and Biotechnology Apr 2020L-Ribose is a non-naturally occurring pentose that recently has become known for its potential application in the pharmaceutical industry, as it is an ideal starting... (Review)
Review
L-Ribose is a non-naturally occurring pentose that recently has become known for its potential application in the pharmaceutical industry, as it is an ideal starting material for use in synthesizing L-nucleosides analogues, an important class of antiviral drugs. In the past few decades, the synthesis of L-ribose has been mainly undertaken through the chemical route. However, chemical synthesis of L-ribose is difficult to achieve on an industrial scale. Therefore, the biotechnological production of L-ribose has gained considerable attention, as it exhibits many merits over the chemical approaches. The present review focuses on various biotechnological strategies for the production of L-ribose through microbial biotransformation and enzymatic catalysis, and in particular on an analysis and comparison of the synthetic methods and different enzymes. The physiological functions and applications of L-ribose are also elucidated. In addition, different sugar isomerases involved in the production of L-ribose from a number of sources are discussed in detail with regard to their biochemical properties. Furthermore, analysis of the separation issues of L-ribose from the reaction solution and different purification methods is presented.Key points • l -Arabinose, l -ribulose and ribitol can be used to produce l -ribose by enzymes. • Five enzymes are systematically introduced for production of l -ribose. • Microbial transformation and enzymatic methods are promising for yielding l -ribose.
Topics: Arabinose; Bacteria; Biotechnology; Biotransformation; Enzymes, Immobilized; Isomerases; Ribose
PubMed: 32088757
DOI: 10.1007/s00253-020-10471-9 -
Journal of Microbiology and... Mar 2019L-Arabinose, a five carbon sugar, has not been considered as an important bioresource because most studies have focused on D-xylose, another type of five-carbon sugar... (Review)
Review
L-Arabinose, a five carbon sugar, has not been considered as an important bioresource because most studies have focused on D-xylose, another type of five-carbon sugar that is prevalent as a monomeric structure of hemicellulose. In fact, L-arabinose is also an important monomer of hemicellulose, but its content is much more significant in pectin (3-22%, g/g pectin), which is considered an alternative biomass due to its low lignin content and mass production as juiceprocessing waste. This review presents native and engineered microorganisms that can ferment L-arabinose. is highlighted as the most preferred engineering host for expressing a heterologous arabinose pathway for producing ethanol. Because metabolic engineering efforts have been limited so far, with this review as momentum, more attention to research is needed on the fermentation of L-arabinose as well as the utilization of pectin-rich biomass.
Topics: Arabinose; Bacteria; Biomass; Ethanol; Fermentation; Fungi; Lignin; Metabolic Engineering; Metabolic Networks and Pathways; Pectins; Pentoses; Polysaccharides; Saccharomyces cerevisiae; Xylose
PubMed: 30786700
DOI: 10.4014/jmb.1812.12015 -
Scientific Reports Apr 2017We describe an integrated and straightforward new analytical protocol that identifies plant gums from various sample sources including cultural heritage. Our approach is...
We describe an integrated and straightforward new analytical protocol that identifies plant gums from various sample sources including cultural heritage. Our approach is based on the identification of saccharidic fingerprints using mass spectrometry following controlled enzymatic hydrolysis. We developed an enzyme cocktail suitable for plant gums of unknown composition. Distinctive MS profiles of gums such as arabic, cherry and locust-bean gums were successfully identified. A wide range of oligosaccharidic combinations of pentose, hexose, deoxyhexose and hexuronic acid were accurately identified in gum arabic whereas cherry and locust bean gums showed respectively PentHex and Hex profiles. Optimized for low sample quantities, the analytical protocol was successfully applied to contemporary and historic samples including 'Colour Box Charles Roberson &Co' dating 1870s and drawings from the American painter Arthur Dove (1880-1946). This is the first time that a gum is accurately identified in a cultural heritage sample using structural information. Furthermore, this methodology is applicable to other domains (food, cosmetic, pharmaceutical, biomedical).
Topics: Carbohydrate Sequence; Galactans; Gum Arabic; Hexoses; Hexuronic Acids; History, 19th Century; Humans; Mannans; Oligosaccharides; Paintings; Pentoses; Pictorial Works as Topic; Plant Gums; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 28425501
DOI: 10.1038/srep44538