Coloration on Bluish Alginate Films with Amorphous Heterogeneity Thereof.

Using sodium alginate (Alg) aqueous solution containing indigo carmine (IdC) at various concentrations we characterized the rippled surface pattern with micro-spacing on a flexible film as intriguing bluish Alg-IdC iridescence. The characterization was performed using Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, field emission scanning electron microscopy, atomic force microscopy, electron microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction analysis, and photoluminescence detection. The edge pattern on the film had a maximum depth of 825 nm, a peak-to-peak distance of 63.0 nm, and an average distance of 2.34 nm. The center of the pattern had a maximum depth of 343 nm and a peak-to-peak distance of 162 nm. The pattern spacing rippled irregularly, widening toward the center and narrowing toward the edges. The rippled nano-patterned areas effectively generated iridescence. The ultraviolet absorption spectra of the mixture in the 270 and 615 nm ranges were the same for both the iridescent and non-iridescent film surfaces. By adding Ag+ ions to Alg-IdC, self-assembled microspheres were formed, and conductivity was improved. Cross-linked bluish materials were immediately formed by the addition of Ca2+ ions, and the film was prepared by controlling their concentration. This flexible film can be used in applications such as eco-friendly camouflage, anti-counterfeiting, QR code materials for imaging/sensing, and smart hybrid displays.

Development of an integrated mobile application for lifestyle modification in women with polycystic ovarian syndrome.

BACKGROUND: Lifestyle modification is the primary treatment for overweight and obese women with polycystic ovarian syndrome (PCOS). Developing mobile applications that motivate and provide lifestyle modification advice and evidence-based information for women with PCOS is needed. AIMS: This study is aimed at the development of an integrated mobile application for lifestyle modifications in women with PCOS. METHODS: This study is a development study to develop a lifestyle modification mobile application for PCOS based on a systematic review and needs analysis according to the ADDIE model. The survey was conducted consecutively on patients with PCOS who visited a university hospital in Incheon, Republic of Korea from 1 November 2020 to 28 February 2021. The questionnaire was developed based on prior literature, and validity was evaluated by experts. The survey investigated respondents' general characteristics, the perceptions and needs, and the preferred components of integrated mobile application for lifestyle modification. The usability of the application was evaluated by experts. STROBE statement has been followed in this study. RESULTS: The lifestyle modification programme was confirmed to be clinical effect through a systematic review. The necessity application and high scores in preference of all components was confirmed in a survey. The mobile application included every amount of intake, exercise time, menstrual period, and daily weight compared with the target weight and BMI. It also included questionnaires on hirsutism and acne, disease information, and communication with the researcher for counselling purposes. The application will motivate users to participate by giving scores according to a goal achievement each day. In usability test, experts evaluate this mobile application as suitable for use. CONCLUSION: In this study, an integrated mobile application was developed in consideration of the systematic review and needs analysis of women with PCOS. The effectiveness of the application will need to be verified through further research. RELEVANCE TO CLINICAL PRACTICE: This study developed an integrated mobile application including diet and exercise therapy, as well as weight and menstrual period management, questionnaires and disease information. In addition, the mobile application motivates women with PCOS to provide personalised counselling and achieve goals. We expect to use it in future studies for women with PCOS in clinical practice.

Fabrication of innocuous hydrogel scaffolds based on modified dextran for biotissues.

Substrates with basic structures similar to those of living tissues are useful as cellular scaffolds for the preparation of biocompatible and innocuous materials. In this study, a hydrogel matrix was prepared by introducing a functional group capable of forming crosslinks between natural polymers to create a basis for preparing a microenvironment favorable for cell adaptation. The modified dextran hydrogel polymer was designed to mimic the conditions of the extracellular matrix (ECM) as a scaffold. The precursors of the target hydrogel were synthesized using condensation with a stepwise procedure. A delicate hydrogel based on modified dextran was obtained via photo-crosslinking under room temperature at UV-254 nm. The biocompatibility of this hydrogel was verified using green fluorescence images acquired by incubating a cell line. The characteristics of the hydrogel were verified using proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and electrostatic spinning. The crosslinked structure and biocompatibility of the modified hydrogel were confirmed using instrumental analyses and a promising cell culture. Using TGA, the weight losses of precursor and hydrogel were determined to be 90.96% and 39.2%, respectively, up to 600 °C. The diameters of the nanofibers, fabricated via electrospinning, were measured to range from 200 to 500 nm.

Finding of novel lactate utilizing Bacillus sp. YHY22 and its evaluation for polyhydroxybutyrate (PHB) production.

Polyhydroxyalkanoates (PHAs) and their derivatives are biopolymers that have the potential of replacing petroleum-based plastics and can be produced and degraded via bacterial metabolism. However, there are only a few studies on polyhydroxybutyrate (PHB) production using lactate, one of the major waste organic acids that could be implemented in the production of polylactic acid (PLA). Herein, we screened and characterized the PHA-producing microbial strains isolated from saltern soil from Docho Island (South Korea). Among the 24 identified microorganisms that can use lactate as a carbon source, Bacillus sp. YHY22, a newly reported strain, produced the highest amount of PHB: 4.05 g/L with 6.25 g/L dry cell weight, which is 64.7% PHB content under optimal production conditions. Bacillus sp. YHY22 could form the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer with propionate addition. Moreover, Bacillus sp. YHY22 produced PHB in non-sterilized 2% lactate and 8% NaCl marine broth culture medium, suggesting that its production can occur in high salinity media without additional sterilization steps, rendering fermentation cost- and time-efficient.

A Quadruple Coating of Probiotics for Enhancing Intestinal Adhesion and Competitive Exclusion of Salmonella Typhimurium.

Previously, our group showed that a quadruple coating of probiotics resulted in higher survivability of probiotics under high acid, bile salt, and thermal stresses. In this study, we evaluated the effect of the quadruple coating of probiotics on adhesive properties as well as on competitive exclusion of Salmonella Typhimurium in Caco-2 cells. We found that the quadruple coating of probiotics exhibited an overall increased adhesion property (up to 10.8-fold) and increased competitive exclusion of Salmonella Typhimurium (up to 4.3-fold). Thus, this study has significant implications and can lead to the development of methods that can improve the adhesive ability of probiotics as well as the adhesive inhibition of pathogens.

Anti-inflammatory potential of Lactiplantibacillus plantarum IDCC 3501 and its safety evaluation.

This study investigated the anti-inflammatory activity of Lactiplantibacillus plantarum IDCC 3501 isolated from kimchi (Korean fermented food) and its safety. When lipopolysaccharide (LPS)-induced RAW 264.7 macrophages were treated with cell-free supernatant from L. plantarum IDCC 3501, the mRNA expression level of inflammatory markers (i.e., TNF-α, IL-1ß, and IL-6) was significantly reduced. In addition, the decreased cell viability by LPS was recovered and NO production in LPS-induced cell was also decreased. For the safety assessment, the genes responsible for antibiotic resistance and virulence were not detected from the genome analysis of this strain. Consistent with this, minimal inhibitory concentrations against various antibiotics, biogenic amines, and D-lactate production, as well as enzymatic and hemolysis activities, indicated that L. plantarum IDCC 3501 did not produce any harmful compounds during fermentation. Furthermore, no acute toxicity and mortality were observed in a murine mouse model. Based on our findings, L. plantarum IDCC 3501 is safe and beneficial for human consumption.

Safety assessment of Streptococcus thermophilus IDCC 2201 used for product manufacturing in Korea.

Safety evaluation of probiotics has become increasingly important for human consumption in food industry. The aims of this study were to assess safety of Streptococcus thermophilus IDCC 2201 through in vitro and in vivo tests. In results, this strain was found to be negative for hemolytic and ß-glucuronidase activity. In addition, thermophilus IDCC 2201 was susceptible to nine antibiotics suggested by EFSA. In accordance with MIC tests, whole-genome analysis indicated that S. thermophilus IDCC 2201 neither harbors antibiotic resistance nor toxigenic genes. Furthermore, none of the biogenic amines including tyramine and histamine was produced and negligible amounts of D-lactate were produced by S. thermophilus IDCC 2201. Finally, it was confirmed that there was no mortality and toxicity throughout single-dose oral toxicity tests in rats. Therefore, we report that S. thermophilus IDCC 2201 is considered to be safe for human consumption as probiotics.

Production of L-Theanine Using Escherichia coli Whole-Cell Overexpressing γ-Glutamylmethylamide Synthetase with Bakers Yeast.

L-Theanine, found in green tea leaves has been shown to positively affect immunity and relaxation in humans. There have been many attempts to produce L-theanine through enzymatic synthesis to overcome the limitations of traditional methods. Among the many genes coding for enzymes in the L-theanine biosynthesis, glutamylmethylamide synthetase (GMAS) exhibits the greatest possibility of producing large amounts of production. Thus, GMAS from Methylovorus mays No. 9 was overexpressed in several strains including vectors with different copy numbers. BW25113(DE3) cells containing the pET24ma::gmas was selected for strains. The optimal temperature, pH, and metal ion concentration were 50°C, 7, and 5 mM MnCl2, respectively. Additionally, ATP was found to be an important factor for producing high concentration of L-theanine so several strains were tested during the reaction for ATP regeneration. Bakers yeast was found to decrease the demand for ATP most effectively. Addition of potassium phosphate source was demonstrated by producing 4-fold higher L-theanine. To enhance the conversion yield, GMAS was additionally overexpressed in the system. A maximum of 198 mM L-theanine was produced with 16.5 mmol/l/h productivity. The whole-cell reaction involving GMAS has greatest potential for scale-up production of L-theanine.

Increased resistance of a methicillin-resistant Staphylococcus aureus Δagr mutant with modified control in fatty acid metabolism.

Methicillin-resistant Staphylococcus aureus (MRSA) strains are distinct from general Staphylococcus strains with respect to the composition of the membrane, ability to form a thicker biofilm, and, importantly, ability to modify the target of antibiotics to evade their activity. The agr gene is an accessory global regulator of gram-positive bacteria that governs virulence or resistant mechanisms and therefore an important target for the control of resistant strains. However, the mechanism by which agr impacts resistance to ß-lactam antibiotics remains unclear. In the present study, we found the Δagr mutant strain having higher resistance to high concentrations of ß-lactam antibiotics such as oxacillin and ampicillin. To determine the influence of variation in the microenvironment of cells between the parental and mutant strains, fatty acid analysis of the supernatant, total lipids, and phospholipid fatty acids were compared. The Δagr mutant strain tended to produce fewer fatty acids and retained lower amounts of C16, C18 fatty acids in the supernatant. Phospholipid analysis showed a dramatic increase in the hydrophobic longer-chain fatty acids in the membrane. To target membrane, we applied several surfactants and found that sorbitan monolaurate (Span20) had a synergistic effect with oxacillin by decreasing biofilm formation and growth. These findings indicate that agr deletion allows for MRSA to resist antibiotics via several changes including constant expression of mecA, fatty acid metabolism, and biofilm thickening.

Conversion of waste cooking oil into biodiesel using heterogenous catalyst derived from cork biochar.

In this study, a heterogeneous catalyst prepared by pyrolysis of waste cork (Quercus suber) was used for the transesterification of waste cooking oil (WCO). Physicochemical properties of the synthesized biochar catalyst were studied using BET, SEM, FTIR, and XRD. The experiment results demonstrate that heterogeneous catalyst synthesized at 600 °C showed maximum fatty acids methyl esters (FAMEs) conversion (98%) at alcohol:oil (25:1), catalyst loading (1.5% w/v) and temperature 65 °C. Biodiesel produced from WCO (Canola oil) mainly composed of FAMEs in following order C18:1 > C18:2 > C16:0 > C18:0 > C20:0. Properties of produced biodiesel were analysed as cetane number (CN) 50.56, higher heating value (HHV) 39.5, kinematic viscosity (ʋ) 3.9, and density (ρ) 0.87.

The effects of diagnostic hysteroscopy on the reproductive outcomes of infertile women without intrauterine pathologies: a systematic review and meta-analysis.

Purpose: Hysteroscopy can be used both to diagnose and to treat intrauterine pathologies. It is well known that hysteroscopy helps to improve reproductive outcomes by treating intrauterine pathologies. However, it is uncertain whether hysteroscopy is helpful in the absence of intrauterine pathologies. This study aimed to confirm whether hysteroscopy improves the reproductive outcomes of infertile women without intrauterine pathologies. Methods: We conducted a systematic review of 11 studies retrieved from Ovid-MEDLINE, Ovid-Embase, and the Cochrane Library. Two independent investigators extracted the data and used risk-of-bias tools (RoB 2.0 and ROBINS-I) to assess their quality. Results: Diagnostic hysteroscopy prior to in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) was associated with a higher clinical pregnancy rate (CPR) and live birth rate (LBR) than non-hysteroscopy in patients with recurrent implantation failure (RIF) (odds ratio, 1.79 and 1.46; 95% confidence interval, 1.40-2.30 and 1.08-1.97 for CPR and LBR, respectively) while hysteroscopy prior to first IVF was ineffective. The overall meta-analysis of LBR showed statistically significant findings for RIF, but a subgroup analysis showed effects only in prospective cohorts (odds ratio, 1.40 and 1.47; 95% confidence interval, 0.62-3.16 and 1.04-2.07 for randomized controlled trials and prospective cohorts, respectively). Therefore, the LBR should be interpreted carefully and further research is needed. Conclusion: Although further research is warranted, hysteroscopy may be considered as a diagnostic and treatment option for infertile women who have experienced RIF regardless of intrauterine pathologies. This finding enables nurses to educate and support infertile women with RIF prior to IVF/ICSI.

Development of glutaric acid production consortium system with α-ketoglutaric acid regeneration by glutamate oxidase in Escherichia coli.

Glutaric acid is a C5 dicarboxylic acid that can be used as a building block for bioplastics. Although high concentrations of glutaric acid can be produced by fermentation or bioconversion, a large amount of α-ketoglutaric acid (α-KG) is necessary to accept the amine group from 5-aminovaleric acid. To decrease the demand for α-KG, we introduced l-glutamate oxidase (GOX) from Streptomyces mobaraensis in our previous system for cofactor regeneration in combination with a glutaric acid production system from 5-aminovaleric acid. To enhance glutaric acid production, critical factors were optimized such as the expression vector, pH, temperature, and cell ratio. As a result, the demand for α-KG was decreased by more than 6-fold under optimized conditions. Additionally, the effect of catalase was also demonstrated by blocking the degradation of α-KG to succinic acid because of the hydrogen peroxide. Finally, 468.5 mM glutaric acid was produced from 800 mM 5-aminovaleric acid using only 120 mM α-KG. Moreover, this system containing davBA, gabTD-nox, and gox can be applied to produce glutaric acid from L-lysine by reusing α-KG with GOX. This improved cofactor regeneration system has a potential to apply much larger production of glutaric acid.

Chitin biomass powered microbial fuel cell for electricity production using halophilic Bacillus circulans BBL03 isolated from sea salt harvesting area.

Incessant depletion of non-renewable energy sources has gained attention to search for new biological systems to transform organic biomass into electricity using microbial fuel cell (MFC). The main approach of the existing study was to develop a single step process to produce electrical energy from underutilized chitin biomass. Halophilic bacterium Bacillus circulans BBL03 isolated from anodic biofilm showed higher electricity production (26.508 µAcm2) in a natural seawater medium fed with 1.0% chitin. Maximum chitinase activity (94.24 ±â€¯4.2 U mL-1) and N-acetylglucosamine (GlcNAc) production (136.30 ±â€¯2.8 mg g-1 chitin) were achieved at 48 h. Prominent metabolites detected in chitin hydrolysis were lactate, formate, acetate, propionate, and butyrate. Furthermore, cyclic voltammetry (CV) studies revealed the possibility of direct electron transfer by anodic biofilm to anode without any external redox mediators. Polarization and coulombic efficiency (CE) analysis showed maximum power density (PD) 1.742 mWcm2 and 47% CE using 1% chitin as a substrate. Alteration in crystallinity and functional group on chitin were analysed using FTIR and XRD. Therefore, natural seawater-chitin powered MFCs could be a cheap asset for longer electricity production.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) terpolymer production from volatile fatty acids using engineered Ralstonia eutropha.

One of the advantages of microbial synthesis of polyhydroxyalkanoates (PHAs) is the production of diverse polymers with different properties by the addition of different monomers, such as 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx). Considering the number of possible variables, terpolymers can have more variations than copolymers. In this study, we aimed to synthesize the terpolymer P(3HB-co-3HV-co-3HHx) from volatile fatty acids such as propionate and butyrate using the recombinant Ralstonia eutropha strain (Re2133/pCB81), containing deletions in the phaB1, phaB2, and phaB3 genes, and overexpression of synthetic PHA operon (phaC2, phaA, phaJ). This strain produced terpolymers depending on the ratio of two different carbon sources, namely, propionic and butyric acids; however, wild type R. eutropha could not produce the same type of polymer. The incorporation of 3-hydroxyvalerate and 3-hydroxyhexanoate monomers was confirmed by gas chromatography and H-nuclear magnetic resonance spectroscopy, and the parameters affecting the terpolymer composition were obtained based on regression. In addition, the thermal analysis showed that this terpolymer has properties different from those of the copolymer, obtained from the same composition of volatile acids. Depending on the ratio of two volatile acids, the composition of the terpolymer can be regulated resulting in different properties.

Bioconversion of barley straw lignin into biodiesel using Rhodococcus sp. YHY01.

Rhodococcus sp. YHY01 was studied to utilize various lignin derived aromatic compounds. It was able to utilize p-coumaric acid, cresol, and 2,6 dimethoxyphenol and resulted in biomass production i.e. 0.38 g dcw/L, 0.25 g dcw/L and 0.1 g dcw/L, and lipid accumulation i.e. 49%, 40%, 30%, respectively. The half maximal inhibitory concentration (IC50) value for p-coumaric acid (13.4 mM), cresol (7.9 mM), and 2,6 dimethoxyphenol (3.4 mM) was analyzed. Dimethyl sulfoxide (DMSO) solubilized barley straw lignin fraction was used as a carbon source for Rhodococcus sp. YHY01 and resulted in 0.130 g dcw/L with 39% w/w lipid accumulation. Major fatty acids were palmitic acid (C16:0) 51.87%, palmitoleic acid (C16:l) 14.90%, and oleic acid (C18:1) 13.76%, respectively. Properties of biodiesel produced from barley straw lignin were as iodine value (IV) 27.25, cetane number (CN) 65.57, cold filter plugging point (CFPP) 14.36, viscosity (υ) 3.81, and density (ρ) 0.86.

Production of glutaric acid from 5-aminovaleric acid by robust whole-cell immobilized with polyvinyl alcohol and polyethylene glycol.

Glutaric acid is an attractive C5 dicarboxylic acid with wide applications in the biochemical industry. Glutaric acid can be produced by fermentation and bioconversion, and several of its biosynthesis pathways have been well characterized, especially the simple pathway involving glutaric acid from l-lysine using 5-aminovaleric acid. We previously reported the production of glutaric acid using 5-aminovaleric acid and α-ketoglutaric acid by a whole-cell reaction, resulting in a high conversion yield. In this study, we sought to enhance the stability and reusability of this whole-cell system for realizing the efficient production of glutaric acid under harsh reaction conditions. To this end, various matrices were screened to immobilize Escherichia coli whole-cell overexpressing 4-aminobutyrate aminotransferase (GabT), succinate semi-aldehyde dehydrogenase (GabD), and NAD(P)H oxidase (NOX). We ultimately selected a PVA-PEG gel (LentiKats®) for cell entrapment, and several factors of the reaction were optimized. The optimal temperature and pH were 35 °C and 8.5, respectively. Treatment with Tween 80 as a surfactant, as well as additional NOX, was found to be effective. Under the optimized conditions, an immobilized cell retained 55% of its initial activity even after the eighth cycle, achieving 995.2 mM accumulated glutaric acid, whereas free cell lost most of their activity after only two cycles. This optimized whole-cell system can be used in the large-scale production of glutaric acid.

A clean and green approach for odd chain fatty acids production in Rhodococcus sp. YHY01 by medium engineering.

Odd chain fatty acids serve as anti-allergic, anti-inflammatory, and antifungal agents, and are useful for the production of biodiesel. Rhodococcus sp. YHY01 utilizes a wide range of carbon sources and accumulate lipids i.e. fructose (37% w/w dcw) glucose (56% w/w dcw), glycerol (50% w/w dcw), acetate (42% w/w dcw), butyrate (65% w/w dcw), lactate (56% w/w dcw), and propionate (62% w/w dcw). In this study, propionate was proved as the best carbon source and produced 69% odd chain fatty acids of total fatty acids, followed by glycerol (13% odd chain fatty acids of total fatty acids). A synthetic medium optimized with response surface design containing glycerol, propionate, and ammonium chloride (0.32%:0.76%:0.040% w/v) facilitated the production of total fatty acids 69% w/w of dcw, and odd chain fatty acids comprised 85% w/w of total fatty acids. Major odd chain fatty acids were in the order C17:0 > C15:0 > Cis-10-C17:1 > 10Me-C17:0 > C19:0 > Cis-10-C19:1.

Enhanced production of cadaverine by the addition of hexadecyltrimethylammonium bromide to whole cell system with regeneration of pyridoxal-5'-phosphate and ATP.

Cadaverine, also known as 1,5-pentanediamine, is an important platform chemical with a wide range of applications and can be produced either by fermentation or bioconversion. Bioconversion of cadaverine from l-lysine is the preferred method because of its many benefits, including rapid reaction time and an easy downstream process. In our previous study, we replaced pyridoxal-5-phosphate (PLP) with pyridoxal kinase (PdxY) along with pyridoxal (PL) because it could achieve 80% conversion with 0.4 M of l-lysine in 6 h. However, conversion was sharply decreased in the presence of high concentrations of l-lysine (i.e., 1 M), resulting in less than 40% conversion after several hours. In this study, we introduced an ATP regeneration system using polyphosphate kinase (ppk) into systems containing cadaverine decarboxylase (CadA) and PdxY for a sufficient supply of PLP, which resulted in enhanced cadaverine production. In addition, to improve transport efficiency, the use of surfactants was tested. We found that membrane permeabilization via hexadecyltrimethylammonium bromide (CTAB) increased the yield of cadaverine in the presence of high concentrations of l-lysine. By combining these two strategies, the ppk system and addition of CTAB, we enhanced cadaverine production up to 100% with 1 M of l-lysine over the course of 6 h.

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) production from engineered Ralstonia eutropha using synthetic and anaerobically digested food waste derived volatile fatty acids.

Ralstonia eutropha Re2133/pCB81 is able to utilize various volatile fatty acids (VFAs) (acetate, butyrate, lactate, and propionate) for polyhydroxyalkanoates (PHAs) production. Acetate and lactate resulted in poly(3-hydroxybutyrate) P(3HB) production, butyrate in poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx), and propionate in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3-HB-co-3HV). Various biomass yields i.e. (Yx/s, 0.131 ±â€¯0.02 g/g acetate, 0.221 ±â€¯0.02 g/g butyrate, 0.222 ±â€¯0.05 g/g lactate, and 0.225 ±â€¯0.04 g/g propionate) and PHA yields (Yp/s, 0.01 ±â€¯0.001 g/g acetate, 0.11 ±â€¯0.004 g/g butyrate, 0.03 ±â€¯0.001 g/g lactate, and 0.18 ±â€¯0.005 g/g propionate) were observed with the different organic acids. When all the organic acids were mixed together R. eutropha Re2133/pCB81 had the following order of preference; lactate > butyrate > propionate > acetate. A response surface design study showed that in mixtures butyrate is the main organic acid involved in PHA production and acts as a precursor for HHx monomer units to produce copolymer P(3HB-co-3HHx). Food waste ferment (FWF) without any additional nitrogen source and precursors resulted in P(3HB-co-3HHx) accumulation (52 ±â€¯4% w/w with 18.5 ±â€¯3% HHx fraction).

Increased Tolerance to Furfural by Introduction of Polyhydroxybutyrate Synthetic Genes to Escherichia coli.

Polyhydroxybutyrate (PHB), the most well-known polyhydroxyalkanoate, is a bio-based, biodegradable polymer that has the potential to replace petroleum-based plastics. Lignocellulose hydrolysate, a non-edible resource, is a promising substrate for the sustainable, fermentative production of PHB. However, its application is limited by the generation of inhibitors during the pretreatment processes. In this study, we investigated the feasibility of PHB production in E. coli in the presence of inhibitors found in lignocellulose hydrolysates. Our results show that the introduction of PHB synthetic genes (bktB, phaB, and phaC from Ralstonia eutropha H16) improved cell growth in the presence of the inhibitors such as furfural, 4-hydroxybenzaldehyde, and vanillin, suggesting that PHB synthetic genes confer resistance to these inhibitors. In addition, increased PHB production was observed in the presence of furfural as opposed to the absence of furfural, suggesting that this compound could be used to stimulate PHB production. Our findings indicate that PHB production using lignocellulose hydrolysates in recombinant E. coli could be an innovative strategy for cost-effective PHB production, and PHB could be a good target product from lignocellulose hydrolysates, especially glucose.