Identification and characterization of a novel 2R, 3R-Butanediol dehydrogenase from Bacillus sp. DL01

BACKGROUND: 2R,3R-butanediol dehydrogenase (R-BDH) and other BDHs contribute to metabolism of 3R/3S-Acetoin (3R/3S-AC) and 2,3-butanediol (2,3-BD), which are important bulk chemicals used in different industries. R-BDH is responsible for oxidizing the hydroxyl group at their (R) configuration. Bacillus species is a promising producer of 3R/3S-AC and 2,3-BD. In this study, R-bdh gene encoding R-BDH from Bacillus sp. DL01 was isolated, expressed and identified. RESULTS: R-BDH exerted reducing activities towards Diacetyl (DA) and 3R/3S-AC using NADH, and oxidizing activities towards 2R,3R-BD and Meso-BD using NAD+ , while no activity was detected with 2S,3S-BD. The R-BDH showed its activity at a wide range of temperature (25 C to 65 C) and pH (5.0­8.0). The R-BDH activity was increased significantly by Cd2+ when DA, 3R/3S-AC, and Meso-BD were used as substrates, while Fe2+ enhanced the activity remarkably at 2R,3R-BD oxidation. Kinetic parameters of the R-BDH from Bacillus sp. DL01 showed the lowest Km, the highest Vmax, and the highest Kcat towards the racemic 3R/3S-AC substrate, also displayed low Km towards 2R,3R-BD and Meso-BD when compared with other reported R-BDHs. CONCLUSIONS: The R-BDH from Bacillus sp. DL01 was characterized as a novel R-BDH with high enantioselectivity for R-configuration. It considered NAD+ and Zn2+ dependant enzyme, with a significant affinity towards 3R/3S-AC, 2R,3R-BD, and Meso-BD substrates. Thus, R-BDH is providing an approach to regulate the production of 3R/3S-AC or 2,3-BD from Bacillus sp. DL01.

Preparation and Rheological Property of Cross-Linked Sodium Hyaluronate Gel / 中国药学杂志

OBJECTIVE: To prepare crossed-linked sodium hyaluronate (CHA) gel and study its rheological property. METHODS: CHA was prepared using 1, 4-butanediol diglycidyl ether (BDDE). The linear viscoelastic properties and creep recovery of hyalouronan(HA) and CHA were measured with a rheometer. The influencing factors of rheological properties were analyzed, such as concentration, proportion of cross-linker and temperature. RESULTS: Cross-linked sodium hyaluronate gel was prepared. The viscoelasticity was measured with a pair of 20 mm stainless steel plates at the frequency of 1 Hz and shear-strain of 1 Pa at (25±0.1)℃. As shown by the creep recovery test, CHA had a smaller strain and shorter time to recover to the minimum strain than HA, which showed typical linear viscoelastic and creep recovery properties. CONCLUSION: CHA is a non-Newtonian fluid, which is easy to administer and conforms completely to the requirements for viscoelastic supplementation materials for intra-articular injection. Compared with HA, CHA has more advantageous viscoelastic property and stability.

Effect of nitrogen, carbon sources and agitation speed on acetoin production of Bacillus subtilis SF4-3

Background: Currently, microbial fermentation method has become the research hotspot for acetoin production. In our previous work, an acetoin-producing strain, Bacillus subtilis SF4-3, was isolated from Japanese traditional fermented food natto. However, its conversion of glucose to acetoin was relatively low. In order to achieve a high-efficient accumulation of acetoin in B. subtilis SF4-3, main medium components and fermentation conditions were evaluated in this work. Results: The by-products analysis showed that there existed reversible transformation between acetoin and 2,3-butanediol that was strictly responsible for acetoin production in B. subtilis SF4-3. The carbon sources, nitrogen sources and agitation speed were determined to play crucial role in the acetoin production. The optimal media (glucose-H2O 150 g/L, yeast extract 10 g/L, corn steep dry 5 g/L, urea 2 g/L, K2HPO4 0.5 g/L, MgSO4 0.5 g/L) were obtained. Furthermore, the low agitation speed of 300 r/min was found to be beneficial to the reversible transformation of 2,3-butanediol for acetoin production in B. subtilis SF4-3. Eventually, 48.9 g/L of acetoin and 5.5 g/L of 2,3-butanediol were obtained in a 5-L fermenter, and the specific production of acetoin was 39.12% (g/g), which accounted for 79.90% of the theoretical conversion. Conclusions: The results indicated acetoin production of B. subtilis SF4-3 was closely related to the medium components and dissolved oxygen concentrations. It also provided a method for acetoin production via the reversible transformation of acetoin and 2,3-butanediol.

Efficacy and Safety of Sodium Hyaluronate with 1,4-Butanediol Diglycidyl Ether Compared to Sodium Carboxymethylcellulose in Preventing Adhesion Formation after Lumbar Discectomy

OBJECTIVE: Epidural injection of hyaluronic acid may prevent adhesion formation after spine surgery, but the compounds used to stabilize hyaluronidase could interfere with its anti-adhesion effects. The present study was conducted as a clinical trial to evaluate the efficacy and safety of an experimental medical gel in preventing adhesion formation. METHODS: This study was designed as a multicenter, randomized, double-blind, and comparative controlled clinical trial with an observation period of 6 weeks. Subjects were randomly assigned into two groups: group A with sodium hyaluronate + 1,4-butanediol diglycidyl ether (BDDE) and group B with sodium hyaluronate + sodium carboxymethylcellulose (CMC). Visual analogue scale (VAS) of back and leg pain and the Oswestry disability index (ODI) and scar score ratings were assessed after surgery. RESULTS: Mean scar grade was 2.37+/-1.13 in group A and 2.75+/-0.97 in group B, a statistically significant difference (p=0.012). VAS of back and leg pain and ODI scores decreased significantly from baseline to 3 and 6 weeks postoperatively in both groups (p0.3). The number of adverse reactions related to the anti-adhesion gels was not statistically different (p=0.569), but subsequent analysis of nervous adverse reactions showed group B was superior with a statistically difference (p=0.027). CONCLUSION: Sodium hyaluronate with BDDE demonstrated similar anti-adhesion properties to sodium hyaluronate with CMC. But, care should be used to nervous adverse reactions by using sodium hyaluronate with BDDE.

INFLUENCE OF 1-BUTANOL, 1,2-BUTANEDIOL AND 1,2,3,4-BUTANETETROL ON THE ADSORPTION OF b-LACTOGLOBULIN AT THE AIR-WATER INTERFACE / INFLUENCIA DE 1-BUTANOL, 1,2-BUTANODIOL Y 1,2,3,4-BUTANOTETROL EN LA ADSORCIÓN DE b-LACTOGLOBULINA EN LA INTERFASE AIRE-AGUA / INFLUÊNCIA DE 1-BUTANOL, 1,2-BUTANODIOL E 1,2,3,4-BUTANOTETROL NA ADSORÇÃO DE b-LACTOGLOBULINA NA INTERFACE AR-ÁGUA

In this work, a systematic study on the effect of 1-butanol, 1,2-butanediol and 1,2,3,4-butanetetrol (erythritol) on the surface tension of β-lactoglobulin in aqueous solution at pH 6.5 and 298.15 K is presented. The experimental data were used to calculate the surface pressure and were adjusted to different protein adsorption models at the liquid-air interface to explain the behavior of β-lactoglobulin in aqueous solution. The results show that the alcohols produce a significant effect on the adsorption behavior of the protein at the interface that is related to the number of hydroxyl groups.

En este trabajo se presenta un estudio sistemático del efecto de 1-butanol, 1,2-butanodiol y 1,2,3,4-butanotetrol (eritritol) sobre la tensión superficial de la β-lactoglobulina en solución acuosa a 298,15 K. Los datos experimentales fueron usados para calcular la presión superficial y se ajustaron a distintos modelos de adsorción en la interfase líquido-aire para explicar el comportamiento de la β-lactoglobulina en solución acuosa. Los resultados muestran que los alcoholes tienen un efecto significativo en el proceso de adsorción de la proteína en la interfase, relacionado con el número de grupos hidroxilo del alcohol.

Neste trabalho, um estudo sistemático sobre o efeito do 1-butanol, 1,2-butanodiol e 1,2,3,4-butanotetrol (eritritol) sobre a tensão superficial da β-lactoglobulina em soluçãoaquosa em pH 6,5 e 298,15 K é apresentado. Os dados experimentais foram utilizados para calcular a pressão de superfície e foram ajustados para diferentes modelos de adsorção de proteínas na interface líquido-ar para explicar o comportamento de β-lactoglobulina em soluçãoaquosa. Os resultados mostram que os alcoóisproduzem um efeito significativo sobre o comportamento de adsorção da proteína na interface que está relacionado com o número de grupos hidroxila.

Magnesium affects poly(3-hydroxybutyrate-co-4-hydroxybutyrate) content and composition by affecting glucose uptake in Delftia acidovorans

Precise control of polyhydroxyalkanoate (PHA) composition is necessary in order to synthesize polymers with specific properties. Among the various types of PHA that have been identified, those that contain 4-hydroxybutyrate (4HB) monomers are especially useful in the medical and pharmaceutical fields as absorbable biomaterial. In this study, we have investigated the effect of magnesium concentration on the biosynthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] by Delftia acidovorans DS-17. Our results show that, magnesium affects the copolymer content and composition by affecting glucose uptake from the culture medium. Higher concentrations of magnesium resulted in lower molar fractions of 3HB in the copolymer and reduced uptake of glucose. The results show for the first time that magnesium may be used to achieve fine control of biologically synthesized PHA copolymer composition

Research on the Feature of 2,3-Butanediol Post-Treatment for Glutaraldehyde Tanned Bovine Pericardium / 中国医师杂志

0 05), but there were significant difference,as compared with control group (all P

Production of 2,3-Butanediol from Sucrose by Klebsiella pneumoniae NRRL B199 in Batch and Fed-Batch Reactors

In batch mode, Klebsiella pneumoniae growth and 2,3-butanediol/acetoin formation are increasingly inhibited by initial sucrose concentrations (S0) over 60 g/L. At non inhibitory conditions, a maximum sucrose consumption rate of 1,5 g/L/h was measured. With S0=204 g/L however, this rate decreased to 0.15 g/L/h. K. pneumoniae fermented 204 g/L sucrose to produce 84.3 g/L of a mixture 2,3-butanediol/acetoin with a yield of 0.41 g/g and a productivity of 1.06 g/L/h. Higher oxygen transfer rates improved the overall process rate but the product yield was reduced. Avoiding substrate inhibition, by performing the fermentation in fed-batch mode, a final 2,3-butanediol/acetoin concentration of 80.0 g/L was achieved. In this case, a productivity of 2.63 g/L/h and a product yield of 0.37 g/g were calculated.

Em regime descontínuo, o crescimento celular e a formação de 2,3-butanodiol/acetoína por Klebsiella pneumoniae sofrem inibição por concentrações iniciais de sacarose (S0) acima de 60 g/L. Sob condições não inibidoras, uma velocidade máxima de consumo de sacarose de 1,5 g/L/h foi observada. Entretanto, com S0 = 204 g/L, esta velocidade decresceu para 0,15 g/L/h. A fermentação de 204 g/L de sacarose por K. pneumoniae levou à formação de 84,3 g/L de mistura 2,3-butanodiol/acetoína, com uma conversão de 0,41 g/g e uma produtividade de 1,06 g/L/h. Um maior suprimento de oxigênio aumentou a velocidade global do processo mas reduziu a conversão em produto. Em regime descontínuo alimentado, a inibição foi evitada, tendo sido atingida uma concentração final de produtos de 80,0 g/L, com uma produtividade de 2,63 g/L/h e uma conversão de 0,37 g/g.

Analysis of the UV absorbing constituents of the metabolites from UV-B tolerance bacteria and study on its anti-ultraviolet mechanism / 中国海洋药物

Objective The anti-UV-B radiation mechanism of UV-B tolerance strain KFS-9 was studied from the profile of metabolites.Methods The compounds were separated by column chromatography and their structures were elucidated based on GC-MS,LC-TOF-MS,EI-MS and NMR analyses.Results Three unsaturated fatty acids(identified as 9-hexadecenoic acid,9,12-octadecadienoic acid and 11-octadecenoic acid) and 1,2-benzenedicarboxylic acid able to absorb ultraviolet were isolated from the petroleum ether extract of the fermentation liquid of Pantoea agglomerans KFS-9.Fraction(Ⅱ) was isolated from the ethyl acetate extract and was composed of 2,3-butanediol and a series of high unsaturated aroma compounds.Fraction(Ⅱ) had a wide absorption peak,and it could protect E.coli from UV-B damage in some sense.Conclusion Strain KFS-9 produced metabolites that were able to absorb UV to build a natural barrier and so improved the tolerance to UV radiation.The UV-B radiation protection test to the E.coli also showed fraction(Ⅱ) was not the only protector,and there definitely existedother materials and mechanism to protect the strain.