Abstract：
:Three threonine aldolases (TAs) were cloned and overexpressed in Escherichia coli (Aeromonas jandaeil-allo-threonine aldolase, E. colil-threonine aldolase and Thermotoga maritimal-allo-threonine aldolase). A Design of Experiments strategy was used to identify optimal reaction conditions for each enzyme. These conditions were used to characterize the substrate- and stereoselectivity of each TA toward a panel of aldehyde acceptors. In general, the A. jandaei TA performed best, and six representative conversions were scaled up 10-fold in order to develop downstream steps for product isolation. One key improvement was to treat the crude reaction product with Bacillus subtilis glycine oxidase, which eliminated residual starting material and significantly simplified product isolation. NMR studies were used to identify the major and minor diastereomers from the preparative-scale reactions and the absolute configurations for three representative cases.
journal_name
Enzyme Microb Technoljournal_title
Enzyme and microbial technologyauthors
Beaudoin SF,Hanna MP,Ghiviriga I,Stewart JDdoi
10.1016/j.enzmictec.2018.07.004subject
Has Abstractpub_date
2018-12-01 00:00:00pages
1-9eissn
0141-0229issn
1879-0909pii
S0141-0229(18)30197-2journal_volume
119pub_type
杂志文章abstract：:Even though many enzyme processes occur at the interface of an insoluble substrate, these reactions are generally much less studied than homogenous enzyme reactions in the aqueous bulk. Interfacial (or heterogeneous) enzyme reactions involve several reaction steps, and the established experimental approach to elucidat...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2017.06.009
更新日期：2017-10-01 00:00:00
abstract：:Amylosucrase (ASase) has great industrial potential owing to its multifunctional activities, including transglucosylation, polymerization, and isomerization. In the present study, the properties of Deinococcus geothermalis ASase (DGAS) expressed in Corynebacterium glutamicum (cDGAS) and purified via Ni-NTA affinity ch...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2019.109505
更新日期：2020-04-01 00:00:00
abstract：:A method is described for construction of a highly sensitive electrochemical biosensor for detection of glutamate. The biosensor is based on covalent immobilization of glutamate oxidase (GluOx) onto polypyrrole nanoparticles and polyaniline composite film (PPyNPs/PANI) electrodeposited onto Au electrode. The enzyme el...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2014.02.001
更新日期：2014-04-10 00:00:00
abstract：:Direct cellobiose production from cellulose by a genetically modified fungus-Neurospora crassa, was explored in this study. A library of N. crassa sextuple beta-glucosidase (bgl) gene deletion strains was constructed. Various concentrations of cellobiose were detected in the culture broth of the N. crassa sextuple bet...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2012.12.010
更新日期：2013-03-05 00:00:00
abstract：:Two acidic β-glucosidases (βGI and βGII) from the brown rot fungus Fomitopsis palustris were purified to homogeneity by several chromatographic steps. βGI and βGII had molecular weights of 130 and 213 kDa, respectively, and exhibited optimum activity at pH 2.5 and 55°C. The K(m) values of βGI and βGII for p-nitropheny...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2010.12.012
更新日期：2011-04-07 00:00:00
abstract：:Glutaric acid is one of the promising C5 platform compounds in the biochemical industry. It can be produced chemically, through the ring-opening of butyrolactone followed by hydrolysis. Alternatively, glutaric acid can be produced via lysine degradation pathways by microorganisms. In microorganisms, the overexpression...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2018.07.002
更新日期：2018-11-01 00:00:00
abstract：:Alginate was evaluated as an immobilization matrix for enzyme-catalyzed reactions in organic solvents. In contrast to most hydrogels, calcium alginate was found to be stable in a range of organic solvents and to retain the enzyme inside the gel matrix. In hydrophobic solvents, the alginate gel (greater than 95% water)...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(92)90024-i
更新日期：1992-01-01 00:00:00
abstract：:The full utilization of hemicellulose sugars (pentose and exose) present in lignocellulosic material, is required for an efficient bio-based fuels and chemicals production. Two recombinant thermophilic enzymes, an endo-1,4-β-mannanase from Dictyoglomus turgidum (DturCelB) and an α-galactosidase from Thermus thermophil...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2017.12.008
更新日期：2018-04-01 00:00:00
abstract：:The methyl ester of 2-benzoxazolon-3-yl-acetic acid was used as an acyl donor in the penicillin amidase-catalysed transfer reaction to 7-aminodesacetoxycephalosporanic acid. The synthesis of 7-(2-benzoxazolon-3-yl-acetamido)-desacetoxycephalosporanic acid was carried out as a kinetically controlled reaction. A charact...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(92)90144-d
更新日期：1992-06-01 00:00:00
abstract：:Horseradish peroxidase (HRP) was successfully purified from horseradish roots by a two-stage reverse-micellar extraction from the dialyzed aqueous extract. The anionic surfactant AOT dissolved in isooctane was used to produce the reverse-micellar phases. The narrow pH range at which HRP solubilization occurred was exp...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(95)00031-3
更新日期：1996-04-01 00:00:00
abstract：:Different lipases have been immobilized on octyl agarose beads at 1mg/g and at maximum loading, via physical interfacial activation versus the octyl layer on the support. The stability of the preparations was analyzed. Most biocatalysts had the expected result: the apparent stability increased using the highly loaded ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2016.12.002
更新日期：2017-03-01 00:00:00
abstract：:An approach was developed to enhance the efficiency for the bioconversion of 1-(3-hydroxyphenyl)-2-(methyamino)-ethanone to (R)-phenylephrine. The strain Serratia marcescens N10612, giving the benefit of 99% enantiomeric excess in (R)-PE conversion, was used. The fermentation was devised to harvest cells with high hyd...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2015.11.004
更新日期：2016-05-01 00:00:00
abstract：:Outdoor microalgal cultivation with high concentration bicarbonate has been considered as a strategy for reducing contamination and improving carbon supply efficiency. The mechanism responsible for algae's strong tolerance to high bicarbonate however, remains not clear. In this study, we isolated and characterized a s...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2016.02.010
更新日期：2016-06-01 00:00:00
abstract：:3-Mercaptopyruvate (3MPy), a structural analog of 3-mercaptopropionic acid, is a precursor compound for biosynthesis of polythioesters in bacteria. The cost-effectiveness and sustainability of the whole process could be greatly improved by using the cysteine degradation pathway for an intracellular supply of 3MPy. Tra...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2017.01.004
更新日期：2017-04-01 00:00:00
abstract：:Anthocyanin production by strawberry cells depends not only on light intensity but also on the light/dark cycle operation with hour- or second-scale periods. These findings are useful for designing and operating photobioreactors for enhanced anthocyanin production. Intermittent illumination with a second-scale period ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/s0141-0229(00)00143-5
更新日期：2000-05-01 00:00:00
abstract：:This work describes for the first time the green synthesis of neopentyl glycol diheptanoate in a solvent-free medium via an enzymatic pathway. The process has been carried out in an open-air reactor in order to ease water removal through evaporation and shift the chemical equilibrium towards product formation. The inh...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2019.109400
更新日期：2020-01-01 00:00:00
abstract：:Supercritical fluids offer environmental advantages over chemical solvents, while providing enhanced separation and chemical selectivity. The use of supercritical fluids for the recovery of products from biomass and the transformation of selected molecules (to add value) was studied. Free fatty acids were bio-catalyti...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2011.07.004
更新日期：2011-09-10 00:00:00
abstract：:The novel termite gut metagenomic-derived GH11 xylanase gene xyl7 was expressed in Escherichia coli BL21, and the purified XYL7 enzyme exhibited high specific activity (6340U/mg) and broad pH active range of 5.5-10.0. Directed evolution was employed to enhance the thermostability of XYL7; two mutants (XYL7-TC and XYL7...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2014.11.005
更新日期：2015-03-01 00:00:00
abstract：:An analysis developed by Westgate et al. for the digestible energy of edible and inedible biomass, including hydrolysis and fermentation, is reexamined with state-of-the-art values for the harvest index of hydroponic crops. ...
journal_title：Enzyme and microbial technology
pub_type： 评论,杂志文章
doi：10.1016/0141-0229(93)90104-a
更新日期：1993-10-01 00:00:00
abstract：:The characterization of the S' subsite specificity of native and ethylated alpha-chymotrypsin has been studied via acyl transfer reaction in acetonitrile containing 10 vol% of water. Using Ac-Tyr-OEt as acyl donor, we investigated the partitioning of acyl-chymotrypsins between water and amino acid and peptide-derived ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(94)90125-2
更新日期：1994-07-01 00:00:00
abstract：:Filamentous fungal secretomes comprise highly dynamic sets of proteins, including multiple carbohydrate active enzymes (CAZymes) which are able to hydrolyze plant biomass polysaccharides into products of biotechnological interest such as fermentable sugars. In recent years, proteomics has been used to identify and qua...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章,评审
doi：10.1016/j.enzmictec.2017.08.007
更新日期：2018-02-01 00:00:00
abstract：:This study aimed to improve the thermostability of a newly cloned tyrosinase from Streptomyces kathirae SC-1. The POPMuSiC algorithm was applied to predict the folding free energy change (ΔDG) of amino acid substitution. Site-directed mutagenesis was used to construct mutants (Q7K, G234P, and Q7K/G234P), and the mutan...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2015.06.002
更新日期：2015-09-01 00:00:00
abstract：:In our previous study, we produced α-keto acids by using an L-amino acid deaminase PmiLAAD (wide-type) from Proteus mirabilis, however, the catalytic efficiency was low due to its low substrate affinity. In this study, protein engineering of PmiLAAD was performed to improve the α-keto acid production. PmiLAAD was engi...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2019.109393
更新日期：2020-01-01 00:00:00
abstract：:Genetic engineering has been used to modify the proportion of different cellulases produced by a hypercellulolytic Trichoderma reesei mutant strain. A general expression vector, pAMH110, containing the promoter and terminator sequences of the strongly expressed main cellobiohydrolase 1 (cbh1) gene was used to overexpr...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/0141-0229(91)90133-u
更新日期：1991-03-01 00:00:00
abstract：:This study examines a novel method to reduce the probability of disulfide mismatches during the refolding process by the replacement of cysteines within a protein. Specifically, Cys383 of recombinant rat procarboxypeptidase B was replaced by other amino acids to increase the refolding efficiency in vitro. Mutants C383...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2011.04.018
更新日期：2011-07-10 00:00:00
abstract：:Effects of different microaerophilic conditions on cell growth, glucose consumption, hydrogen production and cellular metabolism of wild Enterobacter aerogenes strain and polyphosphate kinase (PPK) overexpressing strain were systematically studied in this paper, using NaH(2)PO(4) as the phosphate sources. Under differ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2010.09.015
更新日期：2011-02-08 00:00:00
abstract：:Isolates from gardening waste compost and 38 culture collection microbes were grown on agar plates at pH 4.0 with the cutinase model substrate polycaprolactone as a carbon source. The strains showing polycaprolactone hydrolysis were cultivated in liquid at acidic pH and the cultivations were monitored by assaying the ...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2013.01.005
更新日期：2013-04-10 00:00:00
abstract：:We have examined the chain length selectivity for a series of acyl donors by lipase B from Candida antarctica (CalB). CalB accepted aliphatic diesters of C4, C6 and C12 chain lengths equally. The introduction of a carbon-carbon double bond into the C4 esters dramatically lowered the rate constant associated with polym...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2014.03.006
更新日期：2014-05-10 00:00:00
abstract：:Progesterone 5β-reductases (P5βRs) are involved in 5β-cardenolide formation by stereo-specific reduction of the △4,5 double bond of steroid precursors. In this study a steroid 5β-reductase was identified in Capsella rubella (CrSt5βR1) and its function in steroid 5β-reduction was validated experimentally. CrSt5βR1 is c...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/j.enzmictec.2019.109483
更新日期：2020-03-01 00:00:00
abstract：:Nitrification kinetics of synthetic saline wastewater was investigated by using an activated sludge unit. Initial experiments were performed with salt-free wastewater to obtain baseline information. Experiments with 3% salt concentration were performed at different sludge ages in order to investigate the system perfor...
journal_title：Enzyme and microbial technology
pub_type： 杂志文章
doi：10.1016/s0141-0229(01)00312-x
更新日期：2001-05-07 00:00:00
