scholarly journals Improved Bio-Synthesis of 2,5-bis(hydroxymethyl)furan by Burkholderia contaminans NJPI-15 With Co-substrate

2021 ◽  
Vol 9 ◽  
Author(s):  
Siyuan Chang ◽  
Xuejun He ◽  
Bingfeng Li ◽  
Xin Pan
Keyword(s):  
Catalytic Performance ◽  
Resting Cells ◽  
Fed Batch ◽  
Whole Cells ◽  
Tolerant Strain ◽  
Burkholderia Contaminans ◽  
Ph Range ◽  
Catalytic Capacity ◽  
Biocatalytic Process ◽  
Bio Synthesis

Upgrading of biomass derived 5-hydroxymethylfurfural (HMF) has attracted considerable interest recently. A new highly HMF-tolerant strain of Burkholderia contaminans NJPI-15 was isolated in this study, and the biocatalytic reduction of HMF into 2,5-bis(hydroxymethyl)furan (BHMF) using whole cells was reported. Co-substrate was applied to improve the BHMF yield and selectivity of this strain as well as HMF-tolerant level. The catalytic capacity of the cells can be substantially improved by Mn2+ ion. The strain exhibited good catalytic performance at a pH range of 6.0–9.0 and a temperature range of 25°C–35°C. In addition, 100 mM HMF could be reduced to BHMF by the B. contaminans NJPI-15 resting cells in presence of 70 mM glutamine and 30 mM sucrose, with a yield of 95%. In the fed-batch strategy, 656 mM BHMF was obtained within 48 h, giving a yield of 93.7%. The reported utilization of HMF to produce BHMF is a promising industrially sound biocatalytic process.

scholarly journals Highly Selective Oxidation of 5-Hydroxymethylfurfural to 5-Hydroxymethyl-2-Furancarboxylic Acid by a Robust Whole-Cell Biocatalyst

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 526 ◽  
Author(s):  
Ran Cang ◽  
Li-Qun Shen ◽  
Guang Yang ◽  
Zhi-Dong Zhang ◽  
He Huang ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
High Selectivity ◽  
Value Added ◽  
Catalytic Performance ◽  
Resting Cells ◽  
Fed Batch ◽  
Reaction Conditions ◽  
Whole Cell Biocatalyst ◽  
Radiation Resistant ◽  
First Time

Value-added utilization of biomass-derived 5-hydroxymethylfurfural (HMF) to produce useful derivatives is of great interest. In this work, extremely radiation resistant Deinococcus wulumuqiensis R12 was explored for the first time as a new robust biocatalyst for selective oxidation of HMF to 5-hydroxymethylfuroic acid (HMFCA). Its resting cells exhibited excellent catalytic performance in a broad range of pH and temperature values, and extremely high tolerance to HMF and the HMFCA product. An excellent yield of HMFCA (up to 90%) was achieved when the substrate concentration was set to 300 mM under the optimized reaction conditions. In addition, 511 mM of product was obtained within 20 h by employing a fed-batch strategy, affording a productivity of 44 g/L per day. Of significant synthetic interest was the finding that the D. wulumuqiensis R12 cells were able to catalyze the selective oxidation of other structurally diverse aldehydes to their corresponding acids with good yield and high selectivity, indicating broad substrate scope and potential widespread applications in biotechnology and organic chemistry.

scholarly journals A monodispersed CuPt alloy: synthesis and its superior catalytic performance in the hydrogen evolution reaction over a full pH range

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12470-12475
Author(s):  
Xinmei Liu ◽  
Chen Liang ◽  
Wenlong Yang ◽  
Chunyang Yang ◽  
Jiaqi Lin ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
High Stability ◽  
Low Cost ◽  
Catalytic Performance ◽  
Ph Range

An effective approach to achieve the low cost and high stability of electro-catalysts for HER.

Isolation of an esterase-producing Trichosporon brassicae and its catalytic performance in kinetic resolution of ketoprofen

2001 ◽  
Vol 47 (12) ◽  
pp. 1101-1106 ◽  
Author(s):  
Duan Shen ◽  
Jian-He Xu ◽  
Peng-Fei Gong ◽  
Hui-Yuan Wu ◽  
You-Yan Liu
Keyword(s):  
Ethyl Ester ◽  
Sole Carbon Source ◽  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Catalytic Performance ◽  
Soil Samples ◽  
Enantioselective Hydrolysis ◽  
Resting Cells ◽  
Enantiomeric Ratio ◽  
Hydrolysis Of

A yeast strain CGMCC 0574, identified as Trichosporon brassicae, was selected from 92 strains for its high (S) selectivity in the hydrolysis of ketoprofen ethyl ester. The effective strains of the microorganisms were isolated from soil samples with the ester as the sole carbon source. The ethyl ester proved to be the best substrate for resolution of ketoprofen among several ketoprofen esters examined. The resting cells of CGMCC 0574 could catalyze the hydrolysis of ketoprofen ethyl ester with an enantiomeric ratio of 44.9, giving (S)-ketoprofen an enantiomeric excess of 91.5% at 42% conversion.Key words: ketoprofen, biocatalytic resolution, enantioselective hydrolysis, microbial esterase, Trichosporon brassicae.

scholarly journals Cofactor Dependence in Furan Reduction by Saccharomyces cerevisiae in Fermentation of Acid-Hydrolyzed Lignocellulose

2005 ◽  
Vol 71 (12) ◽  
pp. 7866-7871 ◽  
Author(s):  
Anneli Nilsson ◽  
Marie F. Gorwa-Grauslund ◽  
Bärbel Hahn-Hägerdal ◽  
Gunnar Lidén
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Degradation Products ◽  
Fed Batch ◽  
Fermentation Rate ◽  
Tolerant Strain ◽  
Acid Hydrolysate ◽  
Hydroxymethyl Furfural ◽  
Cell Extracts ◽  
Sugar Degradation

ABSTRACT A decreased fermentation rate due to inhibition is a significant problem for economic conversion of acid-pretreated lignocellulose hydrolysates to ethanol, since the inhibition gives rise to a requirement for separate detoxification steps. Together with acetic acid, the sugar degradation products furfural and 5-hydroxymethyl furfural are the inhibiting compounds found at the highest concentrations in hydrolysates. These aldehydes have been shown to affect both the specific growth rate and the rate of fermentation by yeast. Two strains of Saccharomyces cerevisiae with different abilities to ferment inhibiting hydrolysates were evaluated in fermentations of a dilute acid hydrolysate from spruce, and the reducing activities for furfural and 5-hydroxymethyl furfural were determined. Crude cell extracts of a hydrolysate-tolerant strain (TMB3000) converted both furfural and 5-hydroxymethyl furfural to the corresponding alcohol at a rate that was severalfold higher than the rate observed for cell extracts of a less tolerant strain (CBS 8066), thereby confirming that there is a correlation between the fermentation rate in a lignocellulosic hydrolysate and the bioconversion capacity of a strain. The in vitro NADH-dependent furfural reduction capacity of TMB3000 was three times higher than that of CBS 8066 (1,200 mU/mg protein and 370 mU/mg protein, respectively) in fed-batch experiments. Furthermore, the inhibitor-tolerant strain TMB3000 displayed a previously unknown NADH-dependent reducing activity for 5-hydroxymethyl furfural (400 mU/mg protein during fed-batch fermentation of hydrolysates). No corresponding activity was found in strain CBS 8066 (<2 mU/mg). The ability to reduce 5-hydroxymethyl furfural is an important characteristic for the development of yeast strains with increased tolerance to lignocellulosic hydrolysates.

scholarly journals Enhanced Fenton-like oxidation of hydroxypropyl guar gum catalyzed by EDTA-metal complexes in a wide pH range

2019 ◽  
Vol 79 (9) ◽  
pp. 1667-1674 ◽  
Author(s):  
Ying Tang ◽  
Huan Liu ◽  
Ling Zhou ◽  
Haomiao Ren ◽  
Hong Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Metal Complexes ◽  
Guar Gum ◽  
Average Molecular Weight ◽  
Oxygen Demand ◽  
Catalytic Performance ◽  
Hydroxypropyl Guar ◽  
Wide Ph Range ◽  
Ph Range ◽  
Hydroxypropyl Guar Gum

Abstract A series of EDTA-metal complexes was prepared for the Fenton oxidation catalysts and Fe(II)L exhibits high catalytic performance for degradation of hydroxypropyl guar gum in a wide pH range 7.0–13.0. The viscosity of hydroxypropyl guar gum can be reduced with the 10.0% H2O2 and 5.0% Fe(II)L. The viscosity average molecular weight of hydroxypropyl guar gum was decreased from almost 2 million to 3,199. Most important of all, the chemical oxygen demand (COD) value can be decreased to 104 mg/L from 8,080 mg/L with enough H2O2, and Fe(II)L also shows great catalytic ability in the degradation of various polymers by H2O2. The proposed mechanism of the activation of H2O2 by the complex was studied.

scholarly journals Bioconversion of AHX to AOH by resting cells of Burkholderia contaminans CH-1

2016 ◽  
Vol 80 (10) ◽  
pp. 2045-2050 ◽  
Author(s):  
Jae-Hoon Choi ◽  
Ayaka Kikuchi ◽  
Panyapon Pumkaeo ◽  
Hirofumi Hirai ◽  
Shinji Tokuyama ◽  
...  
Keyword(s):  
Resting Cells ◽  
Burkholderia Contaminans

scholarly journals Quantitative analysis of proton-linked transport systems. The lactose permease of Escherichia coli

1979 ◽  
Vol 182 (3) ◽  
pp. 687-696 ◽  
Author(s):  
I R Booth ◽  
W J Mitchell ◽  
W A Hamilton
Keyword(s):  
Escherichia Coli ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Protonmotive Force ◽  
Lactose Permease ◽  
Whole Cells ◽  
E Coli ◽  
Ph Dependent ◽  
Ph Range ◽  
External Ph

Evidence is presented that lactose uptake into whole cells of Escherichia coli occurs by symport with a single proton over the range of external pH 6.5–7.7. The proton/lactose stoicheiometry has been measured directly over this pH range by comparison of the initial rates of proton and lactose uptake into anaerobic resting cell suspensions of E. coli ML308. Further, the relationship between the protonmotive force and lactose accumulation has been studied in E. coli ML308-225 over the range of external pH 5.9–8.7. At no point was the accumulation of the beta-galactoside in thermodynamic equilibrium with the protonmotive force. It is concluded that the concentration of lactose within the cell is governed by kinetic factors rather than pH-dependent changes in the proton/substrate stoicheiometry. The relevance of these findings to the model of pH-dependent proton/substrate stoicheiometries derived from studies with E. coli membrane vesicles is discussed.

scholarly journals A multi-enzyme cascade reaction for the production of 6-hydroxyhexanoic acid

2019 ◽  
Vol 74 (3-4) ◽  
pp. 71-76 ◽  
Author(s):  
Vishnu S.T. Srinivasamurthy ◽  
Dominique Böttcher ◽  
Uwe T. Bornscheuer
Keyword(s):  
Escherichia Coli ◽  
Cascade Reactions ◽  
Product Inhibition ◽  
Stirred Tank ◽  
Fed Batch ◽  
Batch Mode ◽  
Whole Cells ◽  
Tank Reactor ◽  
Enzyme Cascade

Abstract Multi-enzyme cascade reactions capture the essence of nature’s efficiency by increasing the productivity of a process. Here we describe one such three-enzyme cascade for the synthesis of 6-hydroxyhexanoic acid. Whole cells of Escherichia coli co-expressing an alcohol dehydrogenase and a Baeyer-Villiger monooxygenase (CHMO) for internal cofactor regeneration were used without the supply of external NADPH or NADP+. The product inhibition caused by the ε-caprolactone formed by the CHMO was overcome by the use of lipase CAL-B for in situ conversion into 6-hydroxyhexanoic acid. A stirred tank reactor under fed-batch mode was chosen for efficient catalysis. By using this setup, a product titre of >20 g L−1 was achieved in a 500 mL scale with an isolated yield of 81% 6-hydroxyhexanoic acid.

scholarly journals Evaluation of P450 monooxygenase activity in lyophilized recombinant E. coli cells compared to resting cells

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thomas Hilberath ◽  
Alessandra Raffaele ◽  
Leonie M. Windeln ◽  
Vlada B. Urlacher
Keyword(s):  
Cytochromes P450 ◽  
Rhodococcus Erythropolis ◽  
Resting Cells ◽  
P450 Monooxygenase ◽  
Monooxygenase Activity ◽  
Whole Cells ◽  
E Coli ◽  
Redox Partner ◽  
Starting Point ◽  
P450 Activity

AbstractCytochromes P450 catalyze oxidation of chemically diverse compounds and thus offer great potential for biocatalysis. Due to the complexity of these enzymes, their dependency of nicotinamide cofactors and redox partner proteins, recombinant microbial whole cells appear most appropriate for effective P450-mediated biocatalysis. However, some drawbacks exist that require individual solutions also when P450 whole-cell catalysts are used. Herein, we compared wet resting cells and lyophilized cells of recombinant E. coli regarding P450-catalyzed oxidation and found out that lyophilized cells are well-appropriate as P450-biocatalysts. E. coli harboring CYP105D from Streptomyces platensis DSM 40041 was used as model enzyme and testosterone as model substrate. Conversion was first enhanced by optimized handling of resting cells. Co-expression of the alcohol dehydrogenase from Rhodococcus erythropolis for cofactor regeneration did not affect P450 activity of wet resting cells (46% conversion) but was crucial to obtain sufficient P450 activity with lyophilized cells reaching a conversion of 72% under the same conditions. The use of recombinant lyophilized E. coli cells for P450 mediated oxidations is a promising starting point towards broader application of these enzymes.

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