Microbiological transformations. Part 48: Enantioselective biohydrolysis of 2-, 3- and 4-pyridyloxirane at high substrate concentration using the Agrobacterium radiobacter AD1 epoxide hydrolase and its Tyr215Phe mutant

N-halosuccinimides (chloro, bromo, and iodo, respectively) were introduced, tested, and applied as efficient and non-metal precatalysts for C-, N-, O-, and X-nucleophilic substitution reactions of alcohols under solvent-free reaction conditions (SFRC) or under high substrate concentration reaction conditions (HCRC) efficiently and selectively, into the corresponding products.

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Synthesis and oxidation of aminoalkyl-onium compounds by pig kidney diamine oxidase

Biochemical Journal ◽

10.1042/bj1220557 ◽

1971 ◽

Vol 122 (4) ◽

pp. 557-567 ◽

Cited By ~ 37

Author(s):

W. G. Bardsley ◽

J. S. Ashford ◽

C. M. Hill

Keyword(s):

Substrate Concentration ◽

Diamine Oxidase ◽

Amino Group ◽

High Substrate Concentration ◽

High Substrate ◽

Pig Kidney ◽

Substrate Interaction ◽

Enzyme Substrate ◽

Potent Inhibition

1. The preparation of a series of compounds derived from diamines by replacing one amino group by a dimethylsulphonium, isothiuronium, trimethylammonium, NN′-dimethylimidazolium or N-methylpyridinium species is described. 2. The behaviour of these compounds as substrates of pig kidney diamine oxidase is reported. All but the trimethylammonium compounds proved to be substrates. 3. Many of these compounds showed potent inhibition at high substrate concentration and this was studied. 4. On the basis of these and other observations a scheme for enzyme–substrate interaction is suggested.

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Effect of Substrate Feeding Concentration on Initial Biofilm Development in Anaerobic Hybrid Reactor

ASEAN Journal on Science and Technology for Development ◽

10.29037/ajstd.357 ◽

2017 ◽

Vol 20 (3&4) ◽

pp. 361-372

Author(s):

B. Suraraksa ◽

A. Nopharatana ◽

P. Chaiprasert ◽

S. Bhumiratana ◽

M. Tanticharoen

Keyword(s):

High Glucose ◽

Glucose Concentration ◽

Substrate Concentration ◽

Early Stage ◽

Hybrid Reactor ◽

High Glucose Concentration ◽

High Substrate Concentration ◽

High Substrate ◽

Low Glucose ◽

Biofilm Development

To elucidate the effect of substrate concentration on biofilm development, glucose concentrations of 500 and 1,000 mg/L were used. At an early stage, biofilm development at both concentrations was not significantly different (P=0.621). After removing suspended biomass at 24 operational hours, the biofilm development at high substrate concentration was higher than at lower concentration. At 72 operational hours, the amounts of attached biomass at low and high glucose feeding were 9.04±1.17 and 28.58±2.72 g VSS/m2, respectively. The activities of acidogens, acetogens, and methanogens at the low glucose concentration were 0.334, 0.016 and 0.003 g COD/g VSS/h, and those at the high glucose concentration were 0.145, 0.003 and 0.001 g COD/g VSS/h, respectively. Moreover, the ratio of methanogenic activity at low glucose concentration was higher than at high glucose concentration. The glucose utilization at low and high feeding concentrations was 33% and 27%, respectively. These results indicated that rapid biofilm development by using high substrate concentration would be less beneficial if unbalance of methanogenic ratio was found in biofilm.

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