HMF Concentration Research Articles

Physicochemical and phytochemical properties of Tunisian carob molasses

Carob molasses is widely consumed in many Mediterranean countries, including Tunisia where it is known as ‘Rub El Kharroub’. The main objective of the present study was to evaluate the physicochemical properties and biological activities of both commercial and homemade Tunisian carob molasses. The physicochemical characterization revealed that the main parameters (color and HMF concentration) were related to non-enzymatic browning reactions occurring during juice concentration. The phytochemical analysis proved that the presence of bioactive compounds (volatile compounds, phenolic substances and products of non-enzymatic browning reactions) in carob molasses samples justify their biological effects (antioxidant and antibacterial activities). Accordingly, such characteristics may qualify Tunisian carob molasses (both homemade and commercial) as nutritious and healthy food that could be directly consumed or used a functional ingredient in food and pharmaceutical industry.

Adsorption isotherm, kinetics simulation and breakthrough analysis of 5-hydroxymethylfurfural adsorption/desorption behavior of a novel polar-modified post-cross-linked poly (divinylbenzene-co-ethyleneglycoldimethacrylate) resin

A polar modified post-cross-linked poly (divinylbenzene-co-ethyleneglycol-dimethacrylate) (PCL-PDE) resin was synthesized by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB), and a post-cross-linked reaction. After characterization, the adsorption behaviors of 5-hydroxymethylfurfural (5-HMF) on PCL-PDE resin were determined in comparison with the starting copolymers PDE resin. The equilibrium adsorption capacity of 5-HMF on PCL-PDE resin was much larger than PDE resin and the increase rate was greater than 52.6%. The equilibrium data of 5-HMF onto PCL-PDE resin were found to be better fitted by the Langmuir isotherm model. The kinetic data shows that the adsorption reached equilibrium in a short time (less than 20 min) can be fitted by the pore diffusion model (PDM) at various operating conditions. The effective pore diffusion coefficient was dependent upon adsorption temperature, and were 6.706 × 10−10, 8.958 × 10−10, 1.136 × 10−9 and 1.429 × 10−9 m2 s−1 at 288, 298, 308 and 318 K, respectively. Furthermore, the effects of feed flow rate (Qf = 0.6, 1.5, 3.0 and 6.0 mL min−1) and initial 5-HMF concentration (cf = 0.52, 1.02, 2.00 and 4.96 g L−1) on the adsorption were investigated systematically. Besides, a general rate model (GRM) was used to predict adsorption breakthrough curves of 5-HMF. The simulation results are highly consistent with the experimental data, indicating that the GRM can successfully simulate this process. In the desorption process, the desorption capacity reaches 99.6% of adsorbed capacity, suggesting that the PCL-PDE resin exhibited good reusability. Therefore, it could be suggested that the PCL-PDE resin has a potential application in the separation and purification of 5-HMF.

Efficient Continuous Production of the Biofuel Additive 5‐(t‐Butoxymethyl) Furfural from 5‐Hydroxymethylfurfural

The catalytic etherification of 5‐hydroxymethylfurfural (HMF) with t‐butanol to a biofuel additive 5‐(t‐butoxymethyl) furfural (t‐BMF) is studied by screening 27 heterogeneous protic and/or Lewis acids. Preyssler heteropolyacid H14[NaP5W30O110] and Montmorillonite‐based CLOI_CSP catalysts are identified as the most efficient ones, allowing the etherification to reach the t‐BMF/HMF equilibrium faster (≈1:1), thus promoting minimum side reactions. Further optimization of the batch experimental conditions, namely catalyst loading, temperature, HMF concentration, time, t‐BMF stability, and additives, allows the t‐BMF/HMF equilibrium to be reached in less than 3 h with outstanding selectivity >95%. Under optimized conditions, CLOI_CSP is reused for four cycles without significant loss of efficiency. In addition, it exhibits high efficiency under flow conditions, allowing continuous production of t‐BMF up to 0.7 g t‐BMF g−1 catalyst min−1 at high concentrations of HMF.

Investigating how biomass hydrolysis derivatives inhibit H2 production by an isolated Clostridium beijerinckii

This study evaluates how fermentation inhibitors derived from biomass, namely 5-hydroxymethylfurfural (HMF), levulinic acid (LA), and formic acid (FA), affect H2 production by a Clostridium beijerinckii strain. The specific fermentative H2 production rate (μH2), bacterial cell growth rate (μ), and substrate (glucose) consumption rate (μS) during fermentation helped to estimate which HMF, LA, and FA concentrations inhibited 50% of the rates (IC50). IC50 for μ was 2.4, 2.7, and 1.4 g/L for HMF, LA, and FA, respectively. HMF inhibited H2 production the most potently and favored the lactate and ethanol pathways. Butyric acid was the only metabolite to be detected in the presence of LA or FA, which attested that these inhibitors completely inhibited the acetate pathway. The glucose consumption rate was the least affected by the inhibitors, and FA was more potent than HMF and LA. This information should be useful for more appropriate biomass feedstock application in fermentative H2 production.

Efficient synthesis of bio-monomer 2,5-furandicarboxylic acid from concentrated 5-hydroxymethylfurfural or fructose in DMSO/H2O mixed solvent

The conversion of concentrated 5-hydroxymethylfurfural (HMF) or fructose to 2,5-furandicarboxylic acid (FDCA), a renewable alternative to petroleum-derived terephthalate acid, is highly desirable but challenging for FDCA production in an industrial scale. In this contribution, DMSO/H2O mixture was demonstrated as an effective medium for the production of FDCA from high concentration of HMF or fructose. For example, FDCA yield up to 93% was achieved at 10 wt% HMF concentration in DMSO/H2O over commercially available Ru/C (2 equiv. NaHCO3, 130 °C, 4 MPa O2 and 12 h). Furthermore, an overall FDCA yield of 65% was achieved from concentrated fructose (19 wt%) through a facile two-step process. Notably, it is so far the highest HMF or fructose concentration employed for FDCA formation. As compared to pure water or DMSO, DMSO/H2O mixed system is able to stabilize HMF in an alkaline environment, which allows the efficient oxidation of HMF at high concentrations.

Effect of 1-ethyl-3-methylimidazolium tetrafluoroborate on the phase equilibria for systems containing 5-hydroxymethylfurfural, water, organic solvent in the absence and presence of sodium chloride

HMF (5-hydroxymethylfurfural) is a well-known promising product from hexose dehydration used for production of biofuels and chemicals. Liquid-liquid extraction is an essential process in HMF production to recover HMF from reaction medium. One of the important parameters needed in the extraction process design is liquid-liquid equilibrium (LLE) data. Organic solvent (methyl isobutyl ketone or 2-pentanol) was applied as extraction solvent to induce phase separation and extract HMF from the aqueous solution in the presence of the ionic liquid [EMIM][BF4] (1-ethyl-3-methylimidazolium tetrafluoroborate) and NaCl (sodium chloride). The aim of this study is to investigate the effect of [EMIM][BF4] on the phase equilibria of methyl isobutyl ketone (MIBK) or 2-pentanol, HMF, water systems in the absence and presence of NaCl at 313.15 K and atmospheric pressure (0.1 MPa). The separation factor and the distribution coefficient of HMF were obtained for interpreting liquid-liquid extraction performance. The results indicated that the presence of [EMIM][BF4] caused negative effect on the LLE of organic solvent-HMF-water systems. The slope of tie-lines became more negative with increasing [EMIM][BF4] concentration, indicating lower HMF distribution coefficients and separation factors. However, the presence of NaCl in the HMF aqueous ionic liquid solution can enhance both the separation factor and the distribution coefficient making the HMF extraction more favourable with the HMF distribution coefficient values higher than 1 over the whole range of initial HMF concentrations. According to the results in the present study, MIBK was found superior as an extraction solvent for HMF in the presence of [EMIM][BF4] and NaCl exhibited from the better extraction performance with the separation factors 2.0 times higher than those of 2-pentanol. Furthermore, the NRTL activity coefficient model satisfactorily correlated all the experimental phase equilibrium data provided in this study. The RMSD (root mean square deviations) of the NRTL model were 0.97% and 0.63% for the investigated LLE systems with MIBK and 2-pentanol as solvent in the absence of NaCl, respectively. Whereas, the RMSD of the LLE systems containing NaCl were 0.28% for MIBK-HMF-water-[EMIM][BF4]-NaCl and 0.90% for 2-pentanol-HMF-water-[EMIM][BF4]-NaCl.

The Effect of Sugar Beefeeding on the Concentrations of 5-Hydroxymethylfurfural in Syrian Honey

Samples of Syrian honey were collected directly from beekeepers from across the country. A total of sixteen samples were collected as follows: eight samples of natural nectar honey and eight samples of adulterated honey produced through sugar beefeeding for four months. The study is based on the measurement of 5-Hydroxymethylfurfural (HMF) concentrations in newly collected samples and after one year of storing in room temperature using a methodology based on HPLC with UV detector according to the European Honey Commission. The study showed that HMF concentrations were significantly higher in the adulterated honey samples produced through sugar beefeeding compared with pure honey samples, and after one year of storing in room temperature the concentrations of HMF increased dramatically in all samples and the increase in adulterated samples was significantly higher than that of pure samples. The concentration of newly collected pure samples ranged between (1.3-4.8) mg /kg and those of adulterated samples ranged between (6.6-20.2) mg /kg and after one year of storing the concentration of HMF of pure samples ranged between (7.7-20.3) mg /kg and those of adulterated samples ranged between (40.6-85.2)mg/kg and exceeded the international standards which allow an optimal specification of 40 mg per kg.

Investigation of the conditions for the formation of 5-Hydroxymethylfurfurol in the production of honey wines and sea-buckthorn wine drinks

The article presents experimental data on some mechanisms for the formation of 5-hydroxymethylfurfural (HMF) in the production of sea-buckthorn wines and wine drinks with the addition of honey. Conducted research is necessary because, despite the unconditionally useful properties of honey, it is possible that it has a high content of such chemicals as heavy metals, alkaloids (even in minimal quantities), as well as HMF, the unwanted effect of the latter on the body is mutagenic, genotoxic, organotoxic effects, accompanied by inhibition of a number of metabolic enzymatic processes in the living cell, in addition, the concentration of HMF is used as a parameter characterizing the freshness of honey. In this regard, the Codex Alimentarius Commission has set a maximum limit for HMF in honey - 40mg/kg (80 mg/kg for honey originating from tropical regions), ensuring that honey is not subjected to intense heating during processing and is safe for consumption. Thus, the identification of the kinetic patterns of formation of HMF will allow establishing the optimal parameters for the production of high-quality and safe honey wines and sea-buckthorn wines. It is shown that when preparing this group of drinks, the heating temperature of the product (at the stages of preparing the wort, pasteurizing the finished drink, etc.) should not exceed 60°C with a total heating time of not more than 6 hours and the content of total titrated acids in the drink not more than 7g/dm 3 . The research has scientific and practical significance for beverage producers who use natural honey and vegetable raw materials with high acidity in production, as well as for the regions of Russia engaged in industrial production of honey, since the creation of scientifically based technologies and modes of its storage and processing will improve quality and safety of food produced on its basis.

Characterization, Variables, and Antioxidant Activity of the Maillard Reaction in a Fructose⁻Histidine Model System.

Fructose and its polysaccharides are widely found in fruits and vegetables, with the Maillard reaction of fructose affecting food quality. This study aimed to investigate the Maillard reaction of fructose using a fructose–histidine model system. The reaction process was characterized using fluorescence spectroscopy and ultraviolet spectroscopy. The effects of temperature, initial reactant concentration, initial fructose concentration, initial histidine concentration, and initial pH value on the different stages of the Maillard reaction were studied. Reactant reduction, ultraviolet and fluorescence spectra, acetic acid content, 5-hydroxymethylfurfural (5-HMF) content, and browning intensity were evaluated. The results showed that increasing the temperature and reactant concentration promoted the condensation reaction of fructose and amino acid in the early stage, the formation of intermediate products with ultraviolet absorption and fluorescence in the intermediate stage, and the formation of pigment in the final stage. The 5-HMF concentration decreased with increasing histidine concentration and initial pH value. Changes in the shape of ultraviolet and fluorescence spectra showed that the initial pH value affected not only the reaction rate, but also the intermediate product types. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging rate of the Maillard reaction products increased with increasing temperature, reactant concentration, and initial pH value.

Static microplate fermentation and automated growth analysis approaches identified a highly-aldehyde resistant Saccharomyces cerevisiae strain

The need to replace fossil fuels has motivated research to develop alternative technologies for renewable energy production. For second generation ethanol, this includes the high-throughput screening and selection of yeast strains resistant to inhibitory byproducts of biomass pretreatment. In this work, we evaluated the use of static growth in 96-well microplates as a fermentative assay for Saccharomyces cerevisiae high-throughput screening, together with robust OD measurement correlations that overcome the low absorbance limit found in conventional plate spectrophotometers. This resulted in a method of yeast cultivation in microplates that requires no agitation and results in accurate kinetic parameters that can be used for the screening of S. cerevisiae. In order to automate calculation of these physiological parameters, we created OCHT®, an open-source high-throughput phenotype profiling software for processing, analyzing and visualizing S. cerevisiae growth data. Together, the cultivation standardization and data analysis toolbox allowed the evaluation and comparison of four S. cerevisiae strains in media containing aldehydes growth inhibitors, typically found in hydrolysates produced from sugarcane biomass. We identified FMY001 (SA1-derived) as a tolerant strain at high concentrations of HMF, furfural and vanillin. The individual analysis of segregants derived from FMY001 demonstrated their potential application in emerging biotechnological processes and gave us preliminary insights about the genetic mechanisms related to its high HMF concentration tolerance.

Absorption of 1-Dicysteinethioacetal-5-Hydroxymethylfurfural in Rats and Its Effect on Oxidative Stress and Gut Microbiota.

The absorption of a 5-hydroxymethylfurfural (HMF)-cysteine adduct, 1-dicysteinethioacetal-5-hydroxymethylfurfural (DCH), and its effect on antioxidant activity and gut microbiota were investigated. Results indicated that DCH is more easily absorbed in rats than HMF. Serum DCH concentrations were 15-38-fold of HMF concentrations from 30 to 180 min after intragastrical administration at the level of 100 mg/kg of body weight, and 2.7-4.5% of absorbed DCH was converted to HMF. The malondialdehyde content in the plasma, heart, liver, and kidneys significantly increased after drug (100 mg/kg of bw) administration for 1 week, suggesting that HMF and DCH were oxidative-stress-inducing agents, instead of antioxidant agents, in rats. HMF and DCH also modulated gut microbiota. HMF promoted the growth of Lactobacillus, Tyzzerella, Enterobacter, and Streptococcus. DCH increased the ratio of Firmicutes/ Bacteroidetes and promoted the growth of Akkermansia, Shigella, and Escherichia while inhibiting the growth of Lactobacillus.

Enhancement of bio-ethanol production potential of wheat straw by reducing furfural and 5-hydroxymethylfurfural (HMF)

The present study intended to enhance the bioethanol production potential of wheat straw by reducing furfural and 5-hydroxymethylfurfural. The combination of 180 °C and 2% H2SO4 was optimized for pretreatment of wheat straw, which resulted significantly higher total soluble sugar. The maximum amount of furfural and HMF were observed when wheat straw pretreated at 180 to 220 °C, using 4% (v/v) dilute sulfuric acid. Amendment of pretreated acid hydrolysate using activated charcoal (5%, w/v) reduced up to 84.01% furfural and up to 76.42% HMF concentration in filtrate. The maximum ethanol yield of 5.29% (v/v) was obtained from charcoal amended acid hydrolysate, equivalent to 87.9% theoretical yield. Ethanol yield coefficient (Yps) was found to be 0.44 g ethanol g−1 sugar utilized. These results indicate that activated charcoal treated acid hydrolysate will be effective among the available technologies and could make lignocellulosic biomass-based ethanol production process economically viable by maximizing ethanol yield.

Quality assessment and multivariate calibration of 5-hydroxymethylfurfural during a concentration process for clarified apple juice

Variations in the quality of clarified apple juices subjected to a lab-scale concentration process were assessed. The processing conditions were similar to those used in an industrial three-effects evaporator: 85°C for 25 minutes during the first effect (E1), 75°C for 13 minutes during the second effect (E2) and 58°C for 20 minutes for the third effect (E3). The following parameters were measured at different times from samples of the three effects: Brix content, absorbance spectrum (200 to 670 nm), processing temperature, viscosity, pH, activity of water (Aw) and 5-hydroxymethylfurfural (HMF) concentration (measured via HPLC). The highest increase in HMF occurred during E3, reaching a concentration of 22.26 ± 1.32 mg/kg, with a Brix content of 65.93 ± 0.95. Such HMF concentrations were just below the European Food Regulation Standards. An increase of HMF correlated well with a decrease of Aw and pH. Absorbance spectral values within the UV range increased with increasing processing time, reflecting the non-enzymatic browning effect. Additionally, at measurements above 50° Brix, the effect of temperature and the Brix content had a significant effect on the viscosity. Partial least squares (PLS) regression and pre-processing data under an Orthogonal signal correction OSC + Wavelets (DWT) scenario yielded a multivariate calibration model that accurately predicted the appearance of HMF during the concentration process (R2 0.947). The proposed methodology may serve as an early warning against a critical threshold of HMF by offering a simple and fast physic-chemical analysis conventionally measured by most of the juice processing industry.

Proximate composition and the production of fermentable sugars, levulinic acid, and HMF from Gracilaria fisheri and Gracilaria tenuistipitata cultivated in earthen ponds

The red seaweeds are generally known to have a high content of polysaccharides and low content of lignin. They can be used as a bioethanol feedstock and to produce biochemicals. This study was conducted to examine the pretreatment conditions to improve the production of fermentable sugars and by-products from Gracilaria fisheri and Gracilaria. tenuistipitata. The algal materials were gathered from earthen pond cultivation. The pretreatment was conducted at different concentrations of H2SO4 (0.2–1 M) and time (30–150 min) at 95 °C. The proximate composition and contents of glucose, galactose, levulinic acid, and 5-hydroxymethylfurfural (5-HMF) were analyzed. Our results showed high carbohydrate content of 63.01 ± 0.47 g carbohydrate (100 g TS)−1 for G. fisheri and 59.07 ± 0.43 g carbohydrate (100 g TS)−1 for G. tenuistipitata. The optimal pretreatment with 1 M of H2SO4 at 95 °C for 150 min resulted in high concentrations of sugars in G. fisheri (7.86 g L−1 glucose, 8.37 g L−1 galactose) compared to G. tenuistipitata (3.15 g L−1 glucose, 5.75 g L−1 galactose). The pretreatment of the algae resulted in concentrations of 5-HMF for G. fisheri and G. tenuistipitata of 1.55 and 1.42 g L−1, respectively. The levulinic acid concentration was 3.66 g L−1 for G. fisheri and 6.12 g L−1 for G. tenuistipitata. Gracilaria fisheri was more susceptible to the sulfuric acid hydrolysis compared to G. tenuistipitata. Our study revealed that the acid hydrolysis of G. fisheri and G. tenuistipitata can improve the yield of sugars to produce bioethanol feedstocks.

HMF as a Quality Indicator in Garcinia indica Fruit Juice Concentrate

Garcinia indica is commonly found fruit in India and known for its therapeutic applications. In Particular, its fruit juice concentrate is used as a refreshing drink and for certain therapeutic uses. However, this concentrate contains high amount of sugar and the way it is processed may result in undesirable products and quality deterioration. This study investigates the presence of 5-Hydroxymethylfurfural (5-HMF) in the fruit concentrate which is essentially formed from sugar dehydration, especially in the food which undergoes thermal treatment. The three types of samples used for the study are syrups of the fruit prepared domestically, available commercially and the fruit juice without sugar. Concentration of 5-HMF in the above mentioned three samples is 316.224 mg/kg 147.840 mg/kg and 19 mg/kg respectively. 5 -HMF in sugar-containing samples is above maximum tolerance level - 20 mg/kg (EU) and 25 mg/l (IFFJP). This is clearly due to high proportion of sugar in these concentrates and the processing method. These results raise questions upon its quality and warn about the potential risk of formation of 5-HMF. The study further investigates the effects of HMF on its therapeutic value.

Selective Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran or 2-Formyl-5-furancarboxylic Acid in Water by using MgO⋅CeO2 Mixed Oxides as Catalysts.

Mixed oxides based on MgO⋅CeO2 were used as efficient catalysts in the aerobic oxidation of 5-hydroxymethylfurfural (5-HMF) to afford, with very high selectivity, either 2,5-diformylfuran (DFF, 99 %) or 2-formyl-5-furancarboxylic acid (FFCA, 90 %), depending on the reaction conditions. 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA, 57-90 %) was formed only at low concentration of 5-HMF (<0.03 m) or in presence of external bases. The conversion of 5-HMF ranged from a few percent to 99 %, according to the reaction conditions. The oxidation was performed in water, with O2 as oxidant, without any additives. The surface characterization of the catalysts gave important information about their acid-base properties, which drive the selectivity of the reaction towards DFF. FFCA was formed from DFF at longer reaction times. Catalysts were studied by XPS and XRD before and after catalytic runs to identify the reason why they undergo reversible deactivation. XRD showed that MgO is hydrated to Mg(OH)2 , which, even if not leached out, changes the basic properties of the catalyst that becomes less active after some time. Calcination of the recovered catalyst allows recovery of its initial activity. The catalyst is thus recoverable (>99 %) and reusable. The use of mixed oxides allows tuning of the basicity of the catalysts, avoiding the need for external bases for efficient and selective conversion of 5-HMF and waste formation, resulting in an environmentally friendly, sustainable process.

Determination of Furfural and Hydroxymethyl furfural by UV Spectroscopy in ethanol-water hydrolysate of Reed

In this paper a quick method was developed to determine separate furfural and HMF concentrations simultaneously in ethanol-water hydrolysate of reed based on UV spectroscopy. Acid soluble lignin and other interfering substances were first removed by distillation as residue. The distillate was then used for the determination of furfural and HMF by measuring the maximum absorption wavelength and the absorbance at the wavelength. Results showed that the maximum absorption wavelength of the characteristic peak correlated well with the composition of furfural and HMF mixture in an ethanol-water solution, and the absorbance at the maximum absorption wavelength also had an excellent linear relationship with the sum concentration of furfural and HMF in the solution. The separate concentrations of furfural and HMF in a mixture solution could be determined by applying these correlations.

The effect of furfural and 5‐hydroxymethyl furfural on butyric acid fermentation by Clostridium tyrobutyricum

AbstractBACKGROUNDPotential inhibitory effects of byproducts from lignocellulosic hydrolysis process, including furfural and 5‐hydroxymethyl furfural (HMF), on butyric acid fermentation by Clostridium tyrobutyricum were studied by adding furfural (0, 0.3, 0.6, 0.9 and 1.2 g L‐1) and HMF (0, 0.6, 1.2, 1.8 and 2.4 g L‐1) separately into the xylose medium.RESULTSIncreases in furfural or HMF concentration led to reduced butyric acid productivity. Delays on cell growth and xylose consumption were also noticed with increasing concentrations of furfural and HMF. Complete inhibition of C. tyrobutyricum fermentation was observed at 1.2 g L‐1 of furfural, while HMF showed less severe effects, and that C. tyrobutyricum could tolerate up to 2.4 g L‐1 of HMF. Both furfural and HMF could be metabolized by C. tyrobutyricum.CONCLUSIONFurfural at concentrations higher than 0.3 g L‐1 and HMF at concentrations higher than 0.6 g L‐1 can significantly inhibit the butyric acid fermentation of C. tyrobutyricum, and furfural had more severe effects in terms of cell growth and metabolisms. © 2017 Society of Chemical Industry

Effect of 5-hydroxymethylfurfural (5-HMF) on high-rate continuous biohydrogen production from galactose

This study investigated the effect of 5-hydroxymethylfurfural (5-HMF) on high-rate continuous fermentative H2 production in a lab-scale fixed bed reactor (FBR) inoculated with mixed culture granules and fed with 15g/L galactose at a hydraulic retention time of 6h and at 37°C. During the 83days of operation, 5-HMF up to 2.4g/L was spiked into the feedstock. The maximum hydrogen production performance of 26.6L/L-d and 2.9mol H2/mol galactoseadded were achieved at 5-HMF concentration of 0.6g/L. 5-HMF concentration exceeding 0.9g/L not only inhibited hydrogen production but also affected the biofilm structure and microbial community population. However, when 5-HMF was eliminated from the feedstock, the performance and microbial community population were rapidly recovered.

Furfural and 5-hydroxymethyl-furfural degradation using recombinant manganese peroxidase.

Biomass pretreatment-derived degradation compounds, such as furfural and 5-hydroxymethyl-furfural (HMF), inhibit the growth of fermentation microorganisms that utilize biomass to produce fuels and chemicals. Here we report that recombinant manganese peroxidase (rMnP) produced from the yeast Pichia pastoris can degrade furfural and HMF making them less toxic to microorganisms. Treatment with rMnP or manganese(III) acetate reduced furfural and HMF concentrations in a dose-dependent manner. Furfural disappearance was accompanied by malonate disappearance and accumulation of four distinct degradation products. Furfural was more readily degraded by rMnP and manganese(III) acetate than HMF. Growth assays using Saccharomyces cerevisiae indicated that rMnP treatment reduced the toxicity of furfural and HMF. This work provides an avenue to use rMnP to increase the growth of fermentation microorganisms that are inhibited by toxic compounds derived from pretreatment of biomass.