Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is a chemical compound, a simple alcohol, and is often abbreviated as EtOH. Ethanol is a volatile, flammable, colorless liquid with a slight characteristic odor. Ethanol is an important industrial ingredient. It has widespread use as a precursor for other organic compounds such as ethyl halides, ethyl esters, diethyl ether, acetic acid, and ethyl amines. [Wiki](https://en.wikipedia.org/wiki/Ethanol#Feedstock) **Research Findings** - Recombinant strains containing genes coding for xylose reductase (XR) and xylitol dehydrogenase (XDH) from the xyloseutilizing yeast Pichia stipitis have been reported; however, such strains ferment xylose to ethanol poorly. One reason for this may be the low capacity of xylulokinase, the third enzyme in the xylose pathway. To investigate the potential limitation of the xylulokinase step, we have overexpressed the endogenous gene for this enzyme (XKS1) in S. cerevisiae that also expresses the P. stipitis genes for XR and XDH. The metabolism of this recombinant yeast was further investigated in pure xylose bioreactor cultivation at various oxygen levels. The results clearly indicated that overexpression of XKS1 significantly enhances the specific rate of xylose utilization. In addition, the XKoverexpressing strain can more efficiently convert xylose to ethanol under all aeration conditions studied. One of the important illustrations is the significant anaerobic and aerobic xylose conversion to ethanol by the recombinant Saccharomyces; moreover, this was achieved on pure xylose as a carbon. Under microaerobic conditions, 5.4 g L−1 ethanol was produced from 47 g L−1 xylose during 100 h. Art. [#ARTNUM](#article-25157-2042082999)

Ethylene glycol (IUPAC name: ethane-1,2-diol) is an organic compound with the formula (CH2OH)2. It is mainly used for two purposes, as a raw material in the manufacture of polyester fibers and for antifreeze formulations. It is an odorless, colorless, sweet-tasting, viscous liquid. [Wiki](https://en.wikipedia.org/wiki/Ethylene_glycol) **Research Findings** - These pathways were incorporated into Escherichia coli , and engineered strains produced ethylene glycol from various pentoses, including simultaneously from D xylose and L arabinose; one strain achieved the greatest reported titer of ethylene glycol, 40 g/L, from D xylose at a yield of 0.35 g/g. Art. [#ARTNUM](#article-25156-2214411608) - Here, we developed an alternative xylose utilization pathway that largely bypasses the PPP. In the new pathway, dxylulose is converted to dxylulose1phosphate, a novel metabolite to S. cerevisiae, which is then cleaved to glycolaldehyde and dihydroxyacetone phosphate. This synthetic pathway served as a platform for the biosynthesis of ethanol and ethylene glycol. Art. [#ARTNUM](#article-25156-2462386339) - The important platform chemicals ethylene glycol and glycolic acid were produced via the oxidative Dxylose pathway in the yeast Saccharomyces cerevisiae. The expression of genes encoding Dxylose dehydrogenase (XylB) and Dxylonate dehydratase (XylD) from Caulobacter crescentus and YagE or YjhH aldolase and aldehyde dehydrogenase AldA from Escherichia coli enabled glycolic acid production from Dxylose up to 150 mg/L. In strains expressing only xylB and xylD, 29 mg/L 2keto3deoxyxylonic acid [(S)4,5dihydroxy2oxopentanoic acid]/ (2K3DXA) was produced and Dxylonic acid accumulated to ca. 9 g/L. A significant amount of Dxylonic acid (ca. 14%) was converted to 3deoxypentonic acid (3DPA), and also, 3,4dihydroxybutyric acid was formed. 2K3DXA was further converted to glycolaldehyde when genes encoding by either YagE or YjhH aldolase from E. coli were expressed. Reduction of glycolaldehyde to ethylene glycol by an endogenous aldoketo reductase activity resulted further in accumulation of ethylene glycol of 14 mg/L. Art. [#ARTNUM](#article-25156-2765987778)

2,3-Butanediol (2,3-BD) is a platform chemical that can be converted into a variety of chemicals through dehydrogenation, ketalization, esterification, and dehydration. **Research Findings** - To achieve 2,3-BD production from xylose in yeast, Kim et al. constructed an engineered S. cerevisiae able to efficiently produce 2,3-BD from glucose first, and introduced the XR-XDH pathway into the 2,3-BD strain. Specifically, the 2,3-BD strain was prepared through laboratory evolution of pyruvate decarboxylase (PDC) deficient S. cerevisiae (Δpdc1, Δpdc5) with the heterologous 2,3-BD biosynthetic pathway consisting of acetolactate synthase, acetolactate decarboxylase, and butanediol dehydrogenase, during cultivations in glucose. The resulting strain, overexpressing both the 2,3-BD pathway and the XR-XDH pathway, produced 2,3-BD from xylose with 20.7 g∙L−1 titer and 0.27 g/g yield during batch culture. Additional overexpression of Tal1 enhanced the xylose consumption rate (1.47 ± 0.13 g∙L−1) and 2,3-BD productivity (0.47 ± 0.01 g∙L−1∙h−1) of the strain during xylose culture. - The ability of strain E. cloacae SG1 for utilization various pentoses and hexoses were evaluated and found that the strain can utilize both arabinose and glucose with a comparable 2,3butanediol yield. Art. [#ARTNUM](#article-25171-2282059219) - Bacillus licheniformis mutants, WX02ΔbudC and WX02ΔgldA, were elucidated for the potential to use Miscanthus as a costeffective biomass to produce optically pure 2,3BD. Both WX02ΔbudC and WX02ΔgldA could efficiently use xylose as well as mixed sugars of glucose and xylose to produce optically pure 2,3BD. Art. [#ARTNUM](#article-25171-2801861631)

1,2,4-Butanetriol (BT) is a four-carbon polyol with three hydrophilic hydroxyl groups. As an important fine chemical, BT has versatile applications in many different fields and attracted considerable interest in the past few years. Nitration of racemic d,l-1,2,4-butanetriol 1 affords the energetic material d,l-1,2,4-butanetriol trinitrate 2, which is less shock sensitive, more thermally stable, and less volatile than nitroglycerin. [Wiki](https://en.wikipedia.org/wiki/1,2,4-Butanetriol) **Research Findings** - Oxidation of dxylose by Pseudomonas fragi provides dxylonic acid in 70% yield. Escherichia coli DH5α/pWN6.186A then catalyzes the conversion of dxylonic acid into d1,2,4butanetriol in 25% yield. P. fragi is also used to oxidize larabinose to a mixture of larabino1,4lactone and larabinonic acid in 54% overall yield. After hydrolysis of the lactone, larabinonic acid is converted to l1,2,4butanetriol in 35% yield using E. coli BL21(DE3)/pWN6.222A. Art. [#ARTNUM](#article-25160-2027683911) - In this study, the metabolic network of Escherichia coli was reconstructed by heterogeneously expressing a keto acid decarboxylase(mdl C) from Pseudomonas putida ATCC12633 and a Dxylose dehydrogenase(xdh) from Caulobacter crescentus CB15, and knocking out xyl A, yjh H and yag E which were the genes of xylose utilization pathway and intermediary metabolite pathway for D1,2,4butanetriol synthesis. The recombinant strain could synthesize D1,2,4butanetriol directly using Dxylose as precursor. Art. [#ARTNUM](#article-25160-2358732798) - In this study, an engineered Escherichia coli strain was constructed to produce BT from xylose, which is a major component of the lignocellulosic biomass. Through the coexpression of a xylose dehydrogenase (CCxylB) and a xylonolactonase (xylC) from Caulobacter crescentus, native E. coli xylonate dehydratase (yjhG), a 2keto acid decarboxylase from Pseudomonas putida (mdlC) and native E. coli aldehyde reductase (adhP) in E. coli BL21 star(DE3), the recombinant strain could efficiently convert xylose to BT. Art. [#ARTNUM](#article-25160-2401937566) - Here we reconstituted a cellfree system in vitro using purified enzymes to produce BT from Dxylose. The factors that influencing the efficiency of cellfree system, including enzyme concentration, reaction buffer, pH, temperature, metal ion additives and cofactors were first identified to define optimal reaction conditions and essential components for the cascade reaction. Meanwhile, a natural cofactor recycling system was found in cellfree system. Finally, we were able to convert 18 g/L xylose to 6.1 g/L BT within 40 h with a yield of 48.0%. Art. [#ARTNUM](#article-25160-2912064407)

Cetyl alcohol, also known as hexadecan-1-ol and palmityl alcohol, is a fatty alcohol with the formula CH₃(CH₂)₁₅OH. [Wiki](https://en.wikipedia.org/wiki/Cetyl_alcohol) **Research Findings** - Production of 1-hexadecanol from glucose in S. cerevisiae had been achieved by introducing Tyto alba fatty acyl-CoA reductase and Y. lipolytica ATP-citrate lyase and manipulating endogenous acetyl-CoA and phospholipid metabolisms. Based on this mutant strain, an engineered S. cerevisiae converting xylose into 1-hexadecanol was constructed through optimized overexpression of S. stipitis XR, XDH, and XK, followed by laboratory evolution under xylose conditions. The resulting yeast strain achieved a 1-hexadecanol titer of 0.79 ± 0.10 g∙L−1 in xylose batch and 1.2 g∙L−1 in xylose fed-batch cultures. Yields of 1-hexadecanol from the resulting S. cerevisiae strain grown on xylose were noticeably higher as compared to the case on glucose, in both batch (0.10 g/g xylose, 0.03 g/g glucose) and fed-batch (0.08 g/g xylose, <0.01 g/g glucose) cultures. Art. [#ARTNUM](#article-25188-2905366765)

Glycolic acid (hydroacetic acid or hydroxyacetic acid); chemical formula C2H4O3 (also written as HOCH2CO2H), is the smallest α-hydroxy acid (AHA). This colorless, odorless, and hygroscopic crystalline solid is highly soluble in water. It is used in various skin-care products. [Wiki](https://en.wikipedia.org/wiki/Glycolic_acid) **Research Findings** - The important platform chemicals ethylene glycol and glycolic acid were produced via the oxidative Dxylose pathway in the yeast Saccharomyces cerevisiae. The expression of genes encoding Dxylose dehydrogenase (XylB) and Dxylonate dehydratase (XylD) from Caulobacter crescentus and YagE or YjhH aldolase and aldehyde dehydrogenase AldA from Escherichia coli enabled glycolic acid production from Dxylose up to 150 mg/L. In strains expressing only xylB and xylD, 29 mg/L 2keto3deoxyxylonic acid [(S)4,5dihydroxy2oxopentanoic acid]/ (2K3DXA) was produced and Dxylonic acid accumulated to ca. 9 g/L. A significant amount of Dxylonic acid (ca. 14%) was converted to 3deoxypentonic acid (3DPA), and also, 3,4dihydroxybutyric acid was formed. 2K3DXA was further converted to glycolaldehyde when genes encoding by either YagE or YjhH aldolase from E. coli were expressed. Reduction of glycolaldehyde to ethylene glycol by an endogenous aldoketo reductase activity resulted further in accumulation of ethylene glycol of 14 mg/L. The possibility of simultaneous production of lactic and glycolic acids was evaluated by expression of gene encoding lactate dehydrogenase ldhL from Lactobacillus helveticus together with aldA. Interestingly, this increased the accumulation of glycolic acid to 1 g/L. Art. [#ARTNUM](#article-25190-2765987778)

3-Hydroxypropionic acid (3-HP) is a non-chiral isomer of lactic acid with a β-hydroxyl group. It is a precursor for the synthesis of value-added chemicals including 1,3-propanediol, acrylic acid, and a high value-added biocompatible polymer for medical applications called poly(3-HP). **Research Findings** - We introduced the 3HP biosynthetic pathways via malonylCoA or βalanine intermediates into a xyloseconsuming yeast. Using controlled fedbatch cultivation, we obtained 7.37±0.17g 3HPL1 in 120hours with an overall yield of 29±1%Cmol 3HPCmol1 xylose. Art. [#ARTNUM](#article-25151-2219621454)

Fumaric acid or trans-butenedioic acid is the chemical compound with the formula HO2CCH=CHCO2H. [Wiki](https://en.wikipedia.org/wiki/Fumaric_acid) It can be a precursor for polymerization. **Research Findings** - In this study, a new strain Rhizopus arrhizus RH 7139 # was selected from the R. arrhizus RH 713 through a novel convenient and efficient selection method. Efficient production of fumaric acid (45.31 g/L) from xylose was achieved by the new strain, and the volumetric productivity was still 0.472 g/L h. Moreover, the conversion of xylose reached 73% which is close to the theoretic yield (77%). The production of fumaric acid was increased approximate by 172%, compared with the initial strain counterpart. Art. [#ARTNUM](#article-25176-2041954232) - When using glucose, 58.2 g/L malic acid and 4.2 g/L fumaric acid were produced. When applying xylose or glycerol, both organic acids are produced but the formation of malic acid decreased to 45.4 and 39.4 g/L, respectively. Whereas the fumaric acid concentration was not significantly altered when cultivating with xylose (4.5 g/L). Art. [#ARTNUM](#article-25176-2057194747)

Lactic acid (2-hydroxypropanoic acid) is a three‑carbon carboxylic acid used in food, cosmetic, pharmaceutical, and polymer industries. Current commercial production of lactic acid largely depends on the microbial culture because of mild operating conditions and the high chiral purity of the product. **Research Findings** - Lactobacillus brevis ATCC 367 was selected to produce lactic acid. This strain possesses a relaxed carbon catabolite repression mechanism that can use glucose and xylose simultaneously; however, lactic acid yield was only 0.52 g  g −1 from a mixture of glucose and xylose, and 5.1 g  L −1 of acetic acid and 8.3 g  L −1 of ethanol were also formed during production of lactic acid. The yield was significantly increased and ethanol production was significantly reduced if L. brevis was cocultivated with Lactobacillus plantarum ATCC 21028. L. plantarum outcompeted L. brevis in glucose consumption, meaning that L. brevis was focused on converting xylose to lactic acid and the byproduct, ethanol, was reduced due to less NADH generated in the fermentation system. Sequential cofermentation of L. brevis and L. plantarum increased lactic acid yield to 0.80 g  g −1 from poplar hydrolyzate and increased yield to 0.78  g lactic acid per g of biomass from alkalitreated corn stover with minimum byproduct formation. Art. [#ARTNUM](#article-25163-2005699602) - Production of L(+)lactic acid by R. oryzae using xylose has been reported; however, its yield and conversion rate are poor compared with that of using glucose. In this study, we report an adapted R. oryzae strain HZS6 that significantly improved efficiency of substrate utilization and enhanced production of L(+)lactic acid from corncob hydrolysate. It increased L(+)lactic acid final concentration, yield, and volumetric productivity more than twofold compared with its parental strain. Art. [#ARTNUM](#article-25163-2081748911)

Malic acid is an organic compound with the molecular formula C4H6O5. It is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive. [Wiki](https://en.wikipedia.org/wiki/Malic_acid) **Research Findings** - Molds of the genus Aspergillus are able to produce malic acid in large quantities from glucose and other carbon sources. In order to enhance the production potential of Aspergillus oryzae DSM 1863, production and consumption rates in an established bioreactor batchprocess based on glucose were determined. At 35 °C, up to 42 g/L malic acid was produced in a 168h batch process with fumaric acid as a byproduct. In prolonged shaking flask experiments (353 h), the suitability of the alternative carbon sources xylose and glycerol at a carbontonitrogen (C/N) ratio of 200:1 and the influence of different C/N ratios in glucose cultivations were tested. When using glucose, 58.2 g/L malic acid and 4.2 g/L fumaric acid were produced. When applying xylose or glycerol, both organic acids are produced but the formation of malic acid decreased to 45.4 and 39.4 g/L, respectively. Art. [#ARTNUM](#article-25195-2057194747)

Succinic acid is a dicarboxylic acid with the chemical formula (CH2)2(CO2H)2.[5] The name derives from Latin succinum, meaning amber. Succinic acid is a precursor to some polyesters and a component of some alkyd resins. [Wiki](https://en.wikipedia.org/wiki/Succinic_acid#Applications) **Research Findings** - In this study, corncob hydrolysate was used for succinic acid production. After diluted acid treatment, xylose was released from hemicellulose as the predominant monosaccharide in the hydrolysate, whereas glucose was released very little and most was retained as cellulose in the raw material. Without any detoxification, corncob hydrolysate was used directly as the carbon source in the fermentation. Actinobacillus succinogenes could utilize the sugars in the hydrolysate to produce succinic acid efficiently. Through medium optimization, yeast extract was selected as the nitrogen source and MgCO3 was used to control pH. A total of 23.64 g/l of succinic acid was produced with a yield of 0.58 g/g based on consumed sugar, indicating that the waste corncob residue can be used to produce valueadded chemicals practically. Art. [#ARTNUM](#article-25162-2029670927) - E. coli strain AFP184 was able to utilize all sugars and sugar combinations except sucrose for biomass generation and succinate production. When using xylose as a carbon source, a yield of 0.50 g g 1 was obtained. Art. [#ARTNUM](#article-25162-2031359270) - Metabolically engineered E. coli M6PM was constructed and fermentation with pure sugars revealed that it could utilize xylose and glucose efficiently. E. coli M6PM produced a final succinate concentration of 30.03 ± 0.02 g/L and a yield of 1.09 mol/mol during 72 h dualphase fermentation using elephant grass stalk hydrolysate, which resulted in 64% maximum theoretical yield of succinic acid. Art. [#ARTNUM](#article-25162-2904282411)

Itaconic acid, or methylidenesuccinic acid, is an organic compound. This dicarboxylic acid is a white solid that is soluble in water, ethanol, and acetone. Historically, itaconic acid was obtained by the distillation of citric acid, but currently it is produced by fermentation. It is used in industry as a precursor of polymers used in plastics, adhesives, and coatings. [Wiki] (https://en.wikipedia.org/wiki/Itaconic_acid) **Research Findings** - One hundred A. terreus strains were evaluated for the first time for production of IA from xylose and arabinose. Twenty strains showed good production of IA from the sugars. Among these, six strains (NRRL strains 1960, 1961, 1962, 1972, 66125, and DSM 23081) were selected for further study. One of these strains NRRL 1961 produced 49.8 ± 0.3, 38.9 ± 0.8, 34.8 ± 0.9, and 33.2 ± 2.4 g IA from 80 g glucose, xylose, arabinose and their mixture (1:1:1), respectively, per L at initial pH 3.1 and 33°C. This is the first report on the production of IA from arabinose and mixed sugar of glucose, xylose, and arabinose by A. terreus. Art. [#ARTNUM](#article-25167-2609779945) - In this work, 20 A. terreus strains were evaluated for the first time for IA production from mannose and galactose in shakeflasks at initial pH of 3.1, 33 °C and 200 rpm for 7 days. Strain NRRL1971 possesses the unique ability to produce high concentrations of IA from mannose. It produced 36.4±0.2 g IA from 80 g mannose per liter with a yield of 0.46 g g1 mannose (highest titer reported so far). Art. [#ARTNUM](#article-25167-2760843080)

3-Dehydroshikimic acid is a hydroaromatic precursor to chemicals ranging from lphenylalanine to adipic acid. The concentration and yield of 3dehydroshikimic acid microbially synthesized from various carbon sources has been examined under fedbatch fermentor conditions. Examined carbon sources included dxylose, larabinose, and dglucose. A mixture consisting of a 3:3:2 molar ratio of glucose/xylose/arabinose was also evaluated as a carbon source to model the composition of pentose streams potentially resulting from the hydrolysis of corn fiber. Escherichia coli KL3/pKL4.79B, which overexpresses feedbackinsensitive DAHP synthase, synthesizes higher concentrations and yields of 3dehydroshikimic acid when either xylose, arabinose, or the glucose/ xylose/arabinose mixture is used as a carbon source relative to when glucose alone is used as a carbon source. E. coli KL3/pKL4.124A, which overexpresses transketolase and feedbackinsensitive DAHP synthase, synthesizes higher concentrations and yields of 3dehydroshikimic acid when the glucose/xylose/arabinose mixture is used as the carbon source relative to when either xylose or glucose is used as a carbon source. Art. [#ARTNUM](#article-25222-2001007760)

Polyhydroxyalkanoates or PHAs are polyesters produced in nature by numerous microorganisms, including through bacterial fermentation of sugar or lipids.[1] When produced by bacteria they serve as both a source of energy and as a carbon store. [Wiki](https://en.wikipedia.org/wiki/Polyhydroxyalkanoates) **Research Findings** - Pseudomonas cepacia was evaluated for its ability to utilize xylose, a major hemicellulosic sugar of hardwoods, for the production of the biodegradable, thermoplastic poly(Phydroxybutyrate) (PHB). This culture produced 2.6 g . LI of biomass containing 60% (w/w) PHB when grown in shake flasks on an ammoniumlimited, mineral salts medium containing 10 g. Art. [#ARTNUM](#article-25172-2461176600)

Cadaverine is a foul-smelling diamine compound produced by the putrefaction of animal tissue. Cadaverine is a toxic[1] diamine with the formula NH2(CH2)5NH2, which is similar to putrescine. [Wiki](https://en.wikipedia.org/wiki/Cadaverine) Diaminopentane could be used as a bionylon precursor. **Research Findings** - Corynebacterium glutamicum was metabolically engineered to produce the bionylon precursor 1,5diaminopentane from the hemicellulose sugar xylose. Comparison of a basic diaminopentane producer strain on xylose and glucose feedstocks revealed a 30% reduction in diaminopentane yield and productivity on the pentose sugar. The integration of in vivo and in silico metabolic flux analysis by 13C and elementary modes identified bottlenecks in the pentose phosphate pathway and the tricarboxylic acid cycle that limited performance on xylose. By the integration of global transcriptome profiling, this could be specifically targeted to the tkt operon, genes that encode for fructose bisphosphatase (fbp) and isocitrate dehydrogenase (icd), and to genes involved in formation of lysine (lysE) and Nacetyl diaminopentane (act). This was used to create the C. glutamicum strain DAPXyl1 icdGTG Peftufbp Psodtkt Δact ΔlysE. The novel producer, designated DAPXyl2, exhibited a 54% increase in product yield to 233 mmol mol–1 and a 100% increase in productivity to 1 mmol g–1 h–1 on the xylose substrate. In a fedbatch process, the strain achieved 103 g L–1 of diaminopentane from xylose with a product yield of 32%. Art. [#ARTNUM](#article-25183-2132471240)

**Research Findings** - Amino acids like l-glutamate, l-lysine, l-arginine, and l-ornithine were produced from arabinose as sole carbon source by genetically engineered C. glutamicum strains. Arabinose utilizing amino acid secreting strains were constructed by the heterologous expression of the araBAD operon from E. coli into the corresponding amino acid producing strain of C. glutamicum. l-Glutamate and l-lysine producing arabinose utilizing strains were constructed by the recombination of E. coli araBAD operon in ATCC13032 and DM1729 strains, respectively. l-Ornithine production by the recombinant C. glutamicum strain was obtained by deletion of argR for pathway de-repression and deletion of argF to block l-ornithine conversion. Art. [#ARTNUM](#article-25173-2051523778) - While xylose utilizing C. glutamicum R strains were constructed by heterologous expression of E. coli xylose isomerase gene (xylA), which converts xylose to xylulose, the second enzyme xylulokinase (xylB) is already present in C. glutamicum R. Although in their studies, they focused on organic acid production, this strain is further engineered to produce the amino acid l-alanine. l-Alanine producing C. glutamicum R strain has been created by deleting the genes associated with production of organic acids and overexpressing alanine dehydrogenase gene (alaD) from Lysinibacillus sphaericus. Thus, amino acids were successfully produced by engineered C. glutamicum by utilising pentose sugars. Art. [#ARTNUM](#article-25173-2051523778)

To provide a method of producing a novel sugar derivative by utilizing C6 sugars such as glucose and C5 sugars such as xylose by using microorganisms. SOLUTION: This method of producing chemical compound expressed by the following formula (1) comprises: culturing microorganisms belonging to the genus Myceligenerans in a culture medium including a utilizable carbon source; and generating the chemical compound expressed by the following formula (1) in the culture medium. **Findings** When analyzing the measurements, it was found the compound is glucose 2,6 succinate represented by the following formula (1).

Hexoses and pentoses can be nearly completely converted to **formic acid** through oxidation by hydrogen peroxide at low temperatures. Art. [#ARTNUM](#article-25213-1585797610)

Biomassderived lactic acid is an important renewable chemical building block for synthesizing commodity chemicals, e.g. biodegradable plastics. xylose can be converted to lactic acid by subsequent retro-aldol condensation and dehydration. Art. [#ARTNUM](#article-25204-1982721169) **Research Findings** - This paper reports that hemicellulosic biomass, xylan and xylose, can be converted to lactic acid over a ZrO 2 catalyst starting from pH neutral aqueous solutions. The effects of reaction conditions, including temperature, oxygen partial pressure, biomass loading, and catalyst loading, etc., on the conversions of hemicellulosic biomass and the corresponding yields of lactic acid have been investigated. Molar yields of lactic acid, up to 42% and 30% were produced from xylose and xylan, respectively, under the investigated reaction conditions and with the ZrO 2 catalyst. Art. [#ARTNUM](#article-25204-1982721169)

Levulinic acid, or 4-oxopentanoic acid, is an organic compound with the formula CH3C(O)CH2CH2CO2H. It is classified as a keto acid. This white crystalline solid is soluble in water and polar organic solvents. It is derived from degradation of cellulose and is a potential precursor to biofuels, such as ethyl levulinate. [Wiki](https://en.wikipedia.org/wiki/Levulinic_acid) Liquidstate galactose was converted into levulinic acid via a high-temperature reaction in a batch reactor. Art. [#ARTNUM](#article-25205-2060062622)

Mucic acid, C6H10O8 or HOOC-(CHOH)4-COOH (also known as galactaric or meso-galactaric acid) is an aldaric acid obtained by nitric acid oxidation of galactose or galactose-containing compounds such as lactose, dulcite, quercite, and most varieties of gum. [Wiki](https://en.wikipedia.org/wiki/Mucic_acid) - The method of the present invention can easily synthesize mucic acid in a high yield from galactose and the like under low temperature and atmospheric pressure operating conditions, can be used as an intermediate to produce bio adipic acid, the raw material of nylon 66 that is used as a material for automobile parts, and, therefore, has high industrial applicability. Art. [#ARTNUM](#article-25206-2828893247)

Tetronic acid is a chemical compound, classified as a γ-lactone, with the molecular formula C4H4O3. It interconverts between keto and enol tautomers. In organic synthesis, it is used as a precursor for other substituted and ring-fused furans and butenolides.[4][5] It is also forms the structural core of a class of pesticides, known as tetronic acid insecticides, which includes spirodiclofen and spiromesifen. [Wiki](https://en.wikipedia.org/wiki/Tetronic_acid) In alkaline solution pentoses can be oxidized to tetronic acid. Art. [#ARTNUM](#article-25214-2091071099)

Xylitol, a product from xylose, can be converted to **ethylene glycol** and **propylene glycol** through hydrogenolysis. Art. [#ARTNUM](#article-25216-1990883223); [#ARTNUM](#article-25216-2067211519)

Direct conversion of biomassderived xylose and furfural into levulinic acid, a platform molecule, via acidcatalysis has been accomplished for the first time in dimethoxymethane/methanol. Dimethoxymethane acted as an electrophile to transform furfural into 5hydroxymethylfurfural (HMF). Methanol suppressed both the polymerisation of the sugars/furans and the Aldol condensation of levulinic acid/ester. Art. [#ARTNUM](#article-31252-2587934676)

Xylose can be dehydrated to give furfural in different ways. Furfural is a versatile biomassderived platform compound used for the synthesis of several strategic chemicals. **Research findings:** - This study mainly focused on the dehydration of xylose to furfural with green catalysis. The reaction was under atmospheric pressure, with the 2 2 4 / ZrO SO − as the catalyst plus an inorganic salt (NaCl) as promoter. The results showed that the optimal catalytic reaction conditions were the following conditions: 30 mL of DMSO and 2g xylose, 1 g NaCl, 2.5g 2 2 4 / ZrO SO − and heating for 4 h. It resulted in the maximum yield of 47.7 %. Art. [#ARTNUM](#article-25200-2038521783) - The sonochemically synthesized Zn doped CuO nanoparticles (NPs) were used for the production of furfural. The catalytic activity of the Zn doped CuO NPs was examined, as a model, during the dehydration reaction of xylose to furfural. In addition to that, we have also compared the catalytic activity of the Zn doped CuO NP with ZnO NPs, ZnO bulk, CuO NPs, CuO bulk, etc. This nanoscale catalyst (Zn doped CuO NP) has a large surface area, which enhances its catalytic activity and enables it to completely convert the xylose to furfural at 150 °C within 12 h without any trace of byproducts, as confirmed by HPLC, 13 C NMR and 1 H NMR. HPLC analysis demonstrated that the yield of furfural is up to 86 mol %, compared to the 45 mol % obtained with ZnO NPs, ZnO bulk, CuO NPs, CuO bulk, etc. as catalysts.[#ARTNUM](#article-25200-2922412353) - The C5 xylose sugar syrup can be used to produce additives for animal feeding, furfurol, furfurylic alcohol Art. [#ARTNUM](#article-25200-2243839604) **Notes:** - Furfural can be used as a builiding block for several alcohols/acids.

Galactose and mannose can be converted to 5-HMF by dehydration, with different catalytic methods. Hydroxymethylfurfural (HMF), also 5-(hydroxymethyl)furfural, is an organic compound formed by the dehydration of certain sugars. It is also produced industrially on a modest scale as a carbon-neutral feedstock for the production of fuels and other chemicals. **Research findings** - In this work, Cr, Al and Sn/MCM41 catalysts were prepared by a simple impregnation method and characterized. The conversion of mannose into 5HMF was evaluated in dimethyl sulfoxide (DMSO) solvent. It was found that the assynthesized Sn/MCM41 catalyst showed a superior activity to Cr/MCM41 and Al/MCM41. Mannose could be effectively converted into 5HMF with a yield of ∼45% and ∼88% conversion at 150 °C after 60 min, which were comparable to reported results over heterogeneous catalysts. Art. [#ARTNUM](#article-25201-2891887239) **Notes** 5-HMF can act as building block to: - 2,5-di(hydroxymethyl)furan (DHMF) & 2,5-di(hydroxymethyl)-tetrahydrofuran (DHMTHF). Art. [#ARTNUM](#article-25201-2302279843) - 2,5-dimethylfuran, 2,5-dihydromethylfuran, 2,5-dihydromethyl-tetrahydrofuran, 5-thoxymethylfurfural, 1,6-hexanediol, longchain alkanes, 3-(hydroxymethyl)-cyclopentanone, pxylene, 2,5-diformylfuran, 2,5-furandicarboxylic acid and maleic anhydride. Art. [#ARTNUM](#article-25201-2810881574)

The synthesis of two naturallyoccurring isomers of 3,4dihydroxyproline is reported. l 2,3 cis 3,4 trans 3,4Dihydroxyproline was synthesized from l arabinose in 10 steps and 31% overall yield. The same series of reactions was employed to convert l xylose to l 2,3 trans 3,4 trans 3,4dihydroxyproline. Art. [#ARTNUM](#article-25192-1963983380)

Xylose can be converted to xylitol and xylonic acid in several ways: **Research findings** - Xylose can be reduced to xylitol and oxidized to xylonic acid through electrocatalytic conversion. Art. [#ARTNUM](#article-25221-2060588946) - Xylose can be oxidized to xylonic acid and hydrogenated to xylitol by solid-based metal catalysts. Art. [#ARTNUM](#article-25221-1973098454)