Lactic Acid Yield Research Articles

Hydrothermal Transformation of Glycerol to Lactic Acid in Alkaline Medium Using Cu Catalysts Obtained from Hydrotalcite-Like Precursors

PurposeThe conversion of glycerol into lactic acid in alkaline medium using heterogeneous catalysts has been highlighted and has proved to be an efficient alternative to the conventional fermentative route. This work investigated the production of lactic acid from glycerol in alkaline medium using copper catalysts obtained from hydrotalcite-like precursors in a continuous flow reaction system and the effect of different copper loading on catalytic behaviors in terms of yield and selectivity to lactic acid.MethodsThe catalysts were synthesized by the coprecipitation method and characterized by XRF, XRD, N2 adsorption–desorption, H2-TPR, CO2-TPD, and the copper dispersion (i.e., metal atoms exposed) was determined by N2O oxidation. The reaction was performed for 30 h at 240 °C, 35 atm, using space velocity (WHSV) of 2 h−1, solution of 10 vol% glycerol, and NaOH/glycerol molar ratio of 0.75.ResultsAlthough the 30CuHT catalyst presented higher BET surface areas, Cu dispersion, and basicity than the 20CuHT catalyst, the best results in terms of glycerol conversion (96.5%) and yield (64%) to lactic acid were obtained in the catalytic test performed with the 20CuHT catalyst.ConclusionThis result may be related to the reaction steps that occur in the liquid phase in the presence of the hydroxyl group (\({\text{OH}}^{-}\) Furthermore, the high content of Cu may favor the hydrogenation of the reaction intermediates (2-hydroxypropenal and pyruvaldehyde), increasing the formation of 1,2-propanediol and consequently reducing the yield of lactic acid. The catalytic activity of the reduced and non-reduced catalysts was investigated, and the results showed that copper oxide also has catalytic activity. However, the reduction of copper oxide provides better results.Graphical Abstract

Dual-functional marigold-like ZnxCd1-xS homojunction for selective glucose photoreforming with remarkable H2 coproduction

The global commitment to pivoting to sustainable energy and products calls for technology development to utilize solar energy for hydrogen (H2) and value-added chemicals production by biomass photoreforming. Herein, a novel dual-functional marigold-like ZnxCd1-xS homojunction has been the production of lactic acid with high-yield and H2 with high-efficiency by selective glucose photoreforming. The optimized Zn0.3Cd0.7S exhibits outstanding H2 generation (13.64 mmol h−1 g−1), glucose conversion (96.40%), and lactic acid yield (76.80%), over 272.80 and 19.21 times higher than that of bare ZnS (0.05 mmol h−1 g−1) and CdS (0.71 mmol h−1 g−1) in H2 generation, respectively. The marigold-like morphology provides abundant active sites and sufficient substrates accessibility for the photocatalyst, while the specific role of the homojunction formed by hexagonal wurtzite (WZ) and cubic zinc blende (ZB) in photoreforming biomass has been demonstrated by density functional theory (DFT) calculations. Glucose is converted to lactic acid on the WZ surface of Zn0.3Cd0.7S via the photoactive species O2−, while the H2 is evolved from protons (H+) in H2O on the ZB surface of Zn0.3Cd0.7S. This work paves a promising road for the production of sustainable energy and products by integrating photocatalysis and biorefine.

Production of lactic acid from pasta wastes using a biorefinery approach

A total of 398 kt of pasta waste (PW), generated during the production process of pasta, were produced in 2021. Due to its chemical composition and practically zero cost, PW has already been studied as a raw material for the production of lactic acid (LA) through fermentations. The main objective of this article was to improve the economic viability of the process by replacing commercial enzymes, necessary for starch hydrolysis in PW, with raw enzymes also produced from wastes. Enzyme synthesis was achieved through solid-state fermentation (SsF) of wheat bran by Aspergillus awamori or Aspergillus oryzae at various moisture contents. The maximum amylase activity (52 U/g dry solid) was achieved after 2 days of fermentation with A. awamori at 60% of moisture content. After that, the enzymes were used to hydrolyse PW, reaching 76 g/L of total sugars, 65 g/L of glucose and a yield of 0.72 gglu/gds with the enzymes produced by A. awamori. Subsequently, the hydrolysate was fermented into LA using Bacillus coagulans A559, yielding 52 g/L and 49 g/L with and without yeast extract, respectively. Remarkably, compared to the process with commercial enzymes, a higher LA yield was reached when enzymes produced by SsF were added (0.80 gLA/gglu). Furthermore, the productivities between the two processes were similar (around 3.9 g/L/h) which highlights that yeast extract is not necessary when using enzymes produced by SsF.

Relay photo/thermal catalysis enables efficient cascade upgrading of sugars to lactic acid: Mechanism study and life cycle assessment

Chemocatalytic conversion of biomass-based saccharides to lactic acid (LA) is one of the prospective routes for biomass valorization, but generally suffers from harsh reaction conditions with relatively low selectivity toward CC bond cleavage. Herein, a novel ternary heterostructure g-C3N4/N-TiO2/NiFe-LDH (NTCN/LDH) photocatalyst prepared by a simple wet-chemical method was demonstrated to be high-performance for cascade upgrading of various biomass sugars to LA (up to 99.0 % yield) in H2O at 60 °C under visible-light irradiation for a short time (≥15 min). A relay photo/thermal catalytic mechanism was mainly responsible for the superior performance of NTCN/LDH in LA production, as elucidated by DFT calculations, in which NTCN/LDH provided suitable Lewis acid sites (i.e., adsorption sites) for thermocatalytic sugar isomerization (e.g., glucose-to-fructose conversion), while the constructed double type-II heterojunction could regulate the type and count of the formed reactive oxygen species (dominantly ·O2−) to achieve precise photocatalytic C3-C4 bond breaking. The scale-up test could still maintain 92 % LA yield of the first-time experiment, indicating the eximious industrialization potential of the versatile NTCN/LDH catalyst. In addition, the life cycle assessment illustrated that the entire system has less impact on the environment than the current industrial LA production process.

Highly Selective Photocatalytic Conversion of Glucose on Holo-Symmetrically Spherical Three-Dimensionally Ordered Macroporous Heterojunction Photonic Crystal

Highly Selective Photocatalytic Conversion of Glucose on Holo-Symmetrically Spherical Three-Dimensionally Ordered Macroporous Heterojunction Photonic Crystal

Effect of thermal and ultrasonic pretreatment on lactic acid fermentation of food waste.

Food waste (FW) generation has become one of the largest environmental concerns for human society. Thanks to its chemical features and its high biodegradability, FW can be used as starting platform to produce biocommodities. Lactic acid (LA) is one of those chemicals that is gaining the attention of industry and research for its important role in polylactic acids production. To exploit better the organic content of FW, several FW pretreatments have been proposed in the literature, though none of them were aimed at influencing LA fermentation. Thermal and ultrasonic pretreatment effects on solubilization rates and LA production yields have been investigated in this batch study. The highest solubilization rate was achieved with 30 minutes ultrasonic pretreated FW resulting in a 15% increment in soluble COD (sCOD). The highest LA yield was obtained after 90-minute thermal pretreatment at 80 and 100°C at a yield of 0.49 g LA•g COD-1. This study shows that ultrasonic pretreatment generally performed better than thermal pretreatment when considering the increase in sCOD but caused a reduction in LA concentrations and yields after fermentation with high production of ethanol. The opposite trend was recorded in the thermal pretreated incubations, in which LA was present for 50% of the sCOD with higher LA concentrations of 2.90 g COD•L-1.

Effect of Polydextrose on the Growth of Pediococcus pentosaceus as Well as Lactic Acid and Bacteriocin-like Inhibitory Substances (BLIS) Production.

Pediococcus pentosaceus was cultivated in MRS medium supplemented or not with polydextrose under different conditions in order to evaluate its effect on cell growth, lactic acid and bacteriocin-like inhibitory substance (BLIS) production. Independent variables were pH (4.0, 5.0, 6.0), rotational speed (50, 100, 150 rpm), polydextrose concentration (0.5, 1.0, 1.5%) and temperature (25, 30, 35 °C), while cell concentration and productivity after 24 h, maximum specific growth rate, specific rate of substrate (glucose) consumption, volumetric and specific lactic acid productivities, yields of biomass and lactic acid on consumed substrate were the dependent. The maximum cell concentration (10.24 ± 0.16 gX L−1) and productivity (0.42 ± 0.01 gX L−1 h−1) were achieved at pH 6.0, 35 °C, 150 rpm using 1.5% polydextrose, while the maximum specific growth rate (0.99 ± 0.01 h−1) and yield of biomass (2.96 ± 0.34 gX gS−1) were achieved at the same pH and polydextrose concentration, but at 25 °C and 50 rpm. The specific substrate consumption rate (0.09 ± 0.02 gS gX−1 h−1) and the volumetric lactic acid productivity (0.44 ± 0.02 gP L−1 h−1) were maximized at pH 6.0, 35 °C, 50 rpm and 0.5% polydextrose. BLIS produced in this last run displayed the highest antibacterial activity against Escherichia coli, while the same activity was displayed against Enterococcus faecium using 1.5% polydextrose. These results appear to be quite promising in view of possible production of this BLIS as an antibacterial agent in the food industry.

Highly selective catalytic conversion of raw sugar and sugarcane bagasse to lactic acid over YbCl3, ErCl3, and CeCl3 Lewis acid catalysts without alkaline in a hot-compressed water reaction system

To improve the process efficiency for lactic acid production, catalytic conversion of raw cane sugar and sugarcane bagasse (SCB) to lactic acid under subcritical water condition over Lanthanide catalysts was investigated. The effect of different types of Lanthanide (III) ion catalyst namely YbCl3, ErCl3, and CeCl3 on enhancement of lactic acid (LA) yield, selectivity, turnover number [TON] and turnover frequency [TOF] was studied in the aqueous solution. The results were compared with conventional catalytic reaction for lactic acid production in strongly alkaline solution. For raw sugar-to-lactic acid conversion, ErCl3 catalyst exhibited greatest performance at 240 °C for 15 min and achieve the highest TOF and TON with 91.8% LA yield (91.79%theoretical yield) and 90.5% selectivity. In case of SCB conversion, aqueous ammonia solution (LHWAA) was the best pretreatment to eliminate lignin and hemicellulose and attain cellulose-rich fraction. The LHWAA pretreated SCB conversion to lactic acid over YbCl3 at 240 °C for 15 min achieved supreme performance for highest TOF and TON and accomplished 98.7% LA yield (88.81% theoretical yield) and 94.2% selectivity with trace amount of formic acid, acetic acid and levulinic acid as side products. The findings provided crucial information for a combined cellulose hydrolysis step with catalytic conversion of mono- and polysaccharides to lactic acid in a very shorter time relative to conventional catalytic process and biotechnological fermentation process. Lanthanide catalysts, especially ErCl3 and YbCl3, were found as promising alternative environmentally friendly catalysts providing a potential cost-efficient process of lactic acid from bioresources in a larger scale production.

LED white-light-driven photocatalysis for effective lignocellulose reforming to co-produce hydrogen and value-added chemicals via Zn2/O@IP-g-CN

Synchronous photocatalytic water splitting and the reforming of a biomass-derived feedstock to generate hydrogen and high-value-added chemicals make full utilization of the biomass-water-splitting redox reaction; however, limited successes in this regard have been reported. Herein, incompletely polymerized graphitic carbon nitride co-doped with zinc/oxygen atoms (Zn2/O@IP-g-CN) was prepared via a step-by-step low-temperature calcination process with the assistance of melamine and zinc phthalocyanine, which successfully resulted in simultaneous photocatalytic water splitting and the reforming of biomass-derived monosaccharides to produce hydrogen (11436.7 μmol g−1 h−1) and lactic acid (92.6 %), respectively. Zn2/O@IP-g-CN exhibits a fast separation/migration rate and low resistance compared to those of pure CN, resulting in Zn2/O@IP-g-CN showing enhanced photocatalytic activity. The hydrogen release rate of 86.8 % and lactic acid yield of 89.0 % were retained compared to initial values when Zn2/O@IP-g-CN was reused in 5th cycles. Poisoning experiments indicated that 1O2, ·O2-, ·OH, and h+ were all beneficial for lactic acid production.

Hydrothermal reaction of cellulose in ionic liquid catalyzed by Er(OTf)3

This research explores the potential of ionic liquid to improve lactic acid yield of the hydrothermal reaction of cellulose. The research premise was that ionic liquid dissolved cellulose and water into liquid phase, which would facilitate the formation of glucose and lactic acid using water-tolerant catalyst Erbium (III) trifluoromethanesulfonate (Er(OTf)3). Contrary to the research premise, the experiment revealed that dissolving cellulose in ionic liquid prior to hydrothermal reaction lowered lactic acid yield while increasing hydroxymethylfurfural (HMF) yield. The phenomenon could be attributed to dissociation of water and ionic liquid to give hydronium ion and chloride ion, which subsequently formed hydrochloric acid (HCl). HCl catalyzed cellulose into HMF, in addition to lactic acid. Pressure and pressurized gas had minimal impact on the yield of lactic acid, while the hydrothermal reaction was affected by type of cation and anion of ionic liquid. The highest lactic acid yield of 54.26% was achieved by using 1-butyl-3 methylimidazolium chloride ionic liquid, with 190 °C, 30-min, 10 bar CO2 initial pressure, and Er(OTf)3 50 wt% cellulose. Meanwhile, the highest HMF yield of 66.06% was realized with 1-butyl-3-methylimidazolium hydrogen sulfate in the absence of Er(OTf)3.

“Fish gill” -shaped ordered porous PVA@CNNS hybrid hydrogels with fast charge separation and low resistance for effectively photocatalytic synthesis of lactic acid from biomass-derived sugars

The development of hydrogel-based photocatalysts with three-dimensional ordered porous structure, fast charge separation, and low resistance is significantly in photocatalytic biorefinery but nonetheless poses certain challenges. Herein, we introduced a novel strategy to prepare “Fish gill”-shaped hydrogel-based photocatalysts via freezing-induced encapsulation of ultra-thin carbon nitride nanosheets into a three-dimensional ordered porous polyvinyl alcohol matrix (name as FG-s-PVA@CNNSx). The encapsulation of CNNS in FG-s-PVA@CNNS3 posed no effects on the absorption of visible light but accelerated the transfer/migration of photo-induced charge and reduced the resistance. For photocatalysis, the ordered porous structure of FG-s-PVA@CNNS3 proved to be conducive to the reactants adsorption and mass transfer while the lactic acid yield achieved 92.6%. FG-s-PVA@CNNS3 exhibited excellent stability and reusability, in which the yield of the 10th cycle well reached 95.6% of its first cycle. FG-s-PVA@CNNS3 also displayed exceptional universality wherein the lactic acid yields were 92.6% (glucose), 89.1% (fructose), 88.6% (mannose), 56.0% (rhamnose), 71.1% (arabinose), and 70.9% (xylose). In addition, the effects of various oxidative species on the photocatalytic reaction were systematically discussed, among which ·O2- played a pertinent role. Overall, the construct of hydrogel-based photocatalysts and their application provide a strategy for photocatalytic biorefinery.

Lactic Acid Production from Old Oil Palm Trunk Sap in the Open Batch, Open Repeated Batch, Fed-Batch, and Repeated Fed-Batch Fermentation by Lactobacillus rhamnosus ATCC 10863

The cost of fermentable sugars added as a substrate is one major problem for economic lactic acid (LA) production. Old oil palm trunks (OPT) squeezed sap, the agricultural wastes on replanting and pruning of oil palm (Elaeis guineensis), contained mainly glucose and fructose as a potential feedstock to use as a vast carbon source for LA production. To improve the LA yield and productivity, various fermentation modes were performed by Lactobacillus rhamnosus ATCC 10863 using OPT sap as a basal medium. A modified constant feed mode of fed-batch and repeated fed-batch fermentation using undiluted OPT sap feed medium can achieve a high average LA concentration of 95.94 g/L, yield of 1.04 g/g, and productivity of 6.40 g/L/h) at 11 h cultivation time. It can also provide open and open repeated batch fermentation with an average LA concentration of 91.30 g/L, yield of 0.87 g/g, and productivity of 3.88 g/L/h at 21 h fermentation time.

Pilot Scale for Production and Purification of Lactic Acid from Ceratonia siliqua L. (Carob) Bagasse

The bioconversion of lignocellulose and organic waste bagasse to lactic acid (LA) is an important alternative process requiring valorization as a potentially viable method in the production of pure LA, to be utilized for various purposes. Carob (Ceratonia siliqua L.) biomass was used for the production of LA, using a thermophilic Bacillus coagulans isolate, cultivated in a batch pilot scale of 35 L fermenters without yeast extract supplementation, and operated for 50 h. During the fermentation process, most of the degradable sugar was consumed within 35 h and resulted in the production of 46.9 g/L LA, with a calculated LA yield of 0.72 g/g sugars and productivity at the log phase of 1.69 g/L/h. The use of LA for different industrial applications requires high purity; therefore, a downstream process (DSP) consisting of different purification stages was used, enabling us to reach up to 99.9% (w/w) product purity, which indicates that the process was very effective. The overall almost pure L-LA yield of the DSP was 56%, which indicates that a considerable amount of LA (46%) was lost during the different DSP stages. This is the first study in which carob biomass bagasse has been tested on a pilot scale for LA production, showing the industrial feasibility of the fermentation process.

Effect of MgO addition to Cu-Ni/Al2O3 catalysts on glycerol hydrogenolysis in continuous reactor without external hydrogen

Cu-Ni/xMgO-Al2O3 catalysts with x = 0, 10, 20 and 30 wt% were prepared and evaluated in glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO) at 250 oC, pressure of 40 bar for 30 h, without addition of external hydrogen. The addition of MgO to alumina decreased the surface area, increased the Cu/Ni dispersion and the number of basic sites. The highest 1,2-PDO yield was achieved by Cu-Ni/30%MgO-Al2O3 catalyst: 50% after 6 h of reaction; it decreases to 25% after 30 h. The decrease in 1,2-PDO yield is accompanied by an increase in acetol yield, showing that the rate limiting step for MgO-Al2O3 catalysts is the hydrogenation of acetol to 1,2-PDO because there is not enough hydrogen in reaction medium. For Cu-Ni/MgO catalyst, the reaction pathway changed to the basic route, with preferential formation of lactic acid (50% of lactic acid yield in the first hours of reaction).

Lactic acid from mixed food waste fermentation using an adapted inoculum: Influence of pH and temperature regulation on yield and product spectrum

Environmental conditions (pH and temperature) are expected to influence microbial community composition and product spectrum in mixed-culture food waste (FW) fermentation. However, some conditions may favour growth of multiple organisms that compete for common substrates or consume target metabolites. The inoculum plays an integral role in mixed-culture fermentation, but it is currently unknown how an adapted inoculum, known to selectively produce the target metabolite, would influence fermentation, and how environmental conditions could control fermentation outcomes. Therefore, this study assessed the effects of pH (uncontrolled vs. controlled pH 4.0–6.0) and temperature (35–60 °C) on lactic acid (LA) from synthetic mixed FW batch fermentation (80 gVS·L−1) utilising an adapted fermentation inoculum known to produce significant LA (10% inoculum volume). Concentrations of LA and competing organic acids were measured. Uncontrolled pH encouraged Lactobacillus growth but resulted in a low LA yield due to inhibitory conditions. Controlled pH 6.0 improved LA production but introduced LA consumption and competitive butyrate production. Observed butyrate production was dependent on pH and temperature and correlated with the growth of Clostridium Sensu Stricto 12. At pH 6.0 and 50 °C, observable LA consumption was eliminated, and the LA yield was maximised at 0.55 gLA·gVS−1 (39 gLA·L−1) while Lactobacillus remained dominant. The adapted inoculum effectively promoted LA production, while pH and temperature regulation were effective control levers to target LA.

Combined dehydrogenation of glycerol with catalytic transfer hydrogenation of H2 acceptors to chemicals: Opportunities and challenges.

Catalytic transformation of low-cost glycerol to value-added lactic acid (LA) is considered as one of the most promising technologies for the upgradation of glycerol into renewable products. Currently, research studies reveal that anaerobic transformation of glycerol to LA could also obtain green H2 with the same yield of LA. However, the combined value-added utilization of released H2 with high selectivity of LA during glycerol conversion under mild conditions still remains a grand challenge. In this perspective, for the first time, we conducted a comprehensive and critical discussion on current strategies for combined one-pot/tandem dehydrogenation of glycerol to LA with catalytic transfer hydrogenation of H2 acceptors (such as CO2) to other chemicals. The aim of this overview was to provide a general guidance on the atomic economic reaction pathway for upgrading low-cost glycerol and CO2 to LA as well as other chemicals.

Antagonistic activity of selenium-enriched Bifidobacterium breve against Clostridioides difficile.

Probiotics have the potential to be used in the prevention of Clostridioides difficile infection (CDI). In this study, selenium (Se)-enriched Bifidobacterium breve YH68-Se was obtained under optimal culture conditions with single-factor and response surface optimization. The overall environmental resistance of YH68-Se was superior to that of the parental strain YH68, mainly reflected in the substantial improvement of antioxidant activity and gastrointestinal tolerance. YH68-Se dramatically inhibited C. difficile growth, spore, biofilm, toxin production, and virulence gene expression, rapidly disrupted C. difficile cell membrane permeability and integrity, and altered the membrane proton motive force (PMF), induced a large outflow of intracellular substances and eventually caused bacterial death. The main factor inducing this process originated from the lactic acid (LD) in YH68-Se. In addition, the LD production of YH68 increased with increasing selenite concentration and was accompanied by enhanced activities of thioredoxin reductase (TrxR), glutathione peroxidase (GSH-Px), and increased concentration of autoinducer-2 (AI-2), which may be the crucial factors contributing to the outstanding probiotic properties of YH68-Se and their potent antagonism of C. difficile. KEY POINTS: • Compared with the parental strain B. breve YH68, the environmental resistance of YH68-Se was improved. • YH68-Se was able to produce more lactic acid, which suppressed the important physiological activities of C. difficile and rapidly disrupted their cell membrane structures. • Sodium selenite in the suitable concentration range gradually increases the yield of lactic acid and phenylacetic acid, increased the concentration of autoinducer-2, and enhanced the activities of antioxidant enzymes TrxR and GSH-Px in YH68.

High selective conversion of fructose to lactic acid by photocatalytic reforming of BiOBr/Znx@SnO2-n in alkaline condition

Herein, a novel p-n type BiOBr/Znx@SnO2-n photocatalyst was designed by using BiOBr coupling with large specific surface area Zn doped SnO2 through a facile in situ approach. The composite possesses proper redox potential as well as high efficiency interfacial charge transfer capability. Coupling BiOBr with Zn doped SnO2 is proved efficiency to form a facile bandgap regulation mechanism and could adjust the absorption capacity of visible light, thus enhances the photocatalytic performance effectively. The photocatalyst exhibits high efficiency in photo-reforming of fructose to lactic acid under alkaline conditions, achieving a maximum yield of 79.6% and still achieving a lactic acid yield of 70.7% even after five cycles of recycling. Possible pathways of the lactic acid production were proposed based on the generation of active oxidative radicals and the products detected during the reaction. Therefore, this work provides an effective approach for biomass conversion through rational photocatalyst design.

Potential of New Bacterial Strains for a Multiproduct Bioprocess Application: A Case Study Using Isolates of Lactic Acid Bacteria from Pineapple Silage of Costa Rican Agro-Industrial Residues

Lactic acid bacteria (LAB) with potential for the development of multi-product processes are necessary for the valorization of side streams obtained during the biotechnological production of lactic acid (LA). In this study, 14 LAB strains isolated from pineapple agro-industrial residues in Costa Rica were cultivated in microplates, and the six strains with the highest growth were selected for fermentation in microbioreactors to evaluate the production of LA and acetic acid, and the consumption of glucose. Lacticaseibacillus paracasei 6710 and L. paracasei 6714 presented the highest OD600 values (1.600 and 1.602, respectively); however, the highest LA (in g/L) production was observed in L. paracasei 6714 (14.50 ± 0.20) and 6712 (14.67 ± 0.42). L. paracasei 6714 was selected for bioreactor fermentation and reached a maximum OD600 of 6.3062 ± 0.141, with a LA yield of 84.9% and a productivity of 1.06 g L−1 h−1 after 21 h of fermentation. Finally, lipoteichoic acid (LTA) detection from biomass was performed and the antimicrobial activity of the compounds present in the supernatant was studied. LTA was detected from L. paracasei 6714 biomass, and its supernatant caused significant inhibition of foodborne surrogate microorganisms. LAB isolated from pineapple silage have biotechnological potential for multiproduct processes.

Chemoenzymatic conversion of glycerol to lactic acid and glycolic acid

Catalytic valorization of raw glycerol derived from biodiesel into high-value chemicals has attracted great attention. Here, we report chemoenzymatic cascade reactions that convert glycerol to lactic acid and glycolic acid. In the enzymatic step, a coenzyme recycling system was developed to convert glycerol into 1,3-dihydroxyacetone (DHA) with a yield of 92.3% in potassium phosphate buffer (300 mM, pH 7.1) containing 100 mM glycerol, 2 mM NAD+, 242 U/mL glycerol dehydrogenase-GldA and NADH oxidase-SpNoxK184R at 30 °C. Subsequently, NaOH or NaClO2 catalyzes the formation of lactic acid and glycolic acid from DHA. The high yield of lactic acid (72.3%) and glycolic acid (78.2%) verify the benefit of the chemoenzymatic approaches.Graphical