Biocatalysis in nonaqueous solvents

Khmelnitsky, Yuri L.; Rich, Joseph O.

doi:10.1016/s1367-5931(99)80009-x

Cited by 142 publications

(78 citation statements)

References 42 publications

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“…During microwave irradiation, polar molecules such as water (in the sample) align with the continuously changing magnetic field generated by microwaves. This is supposed to accelerate various chemical, biological, and physical processes (Caddick, 1995;Sridar, 1998;Khmelnitsky and Rich, 1999). Microwave treatment brings about greater accessibility of the susceptible bonds and hence a much more efficient chemical reaction (Roy et al 2003).…”

Section: Preparation Of Chitosanmentioning

confidence: 99%

Removal of heavy metal from industrial wastewater using chitosan coated oil palm shell charcoal

Nomanbhay¹,

Palanisamy²

2005

Electro Journal of Biotech

330

174

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This research focuses on understanding biosorption process and developing a cost effective technology for treatment of heavy metals-contaminated industrial wastewater. A new composite biosorbent has been prepared by coating chitosan onto acid treated oil palm shell charcoal (AOPSC). Chitosan loading on the AOPSC support is about 21% by weight. The shape of the adsorbent is nearly spherical with particle diameter ranging 100~150 µm. The adsorption capacity of the composite biosorbent was evaluated by measuring the extent of adsorption of chromium metal ions from water under equilibrium conditions at 25ºC. Using Langmuir isotherm model, the equilibrium data yielded the following ultimate capacity values for the coated biosorbent on a per gram basis of chitosan: 154 mg Cr/g. Bioconversion of Cr (VI) to Cr (III) by chitosan was also observed and had been shown previously in other studies using plant tissues and mineral surfaces. After the biosorbent was saturated with the metal ions, the adsorbent was regenerated with 0.1 M sodium hydroxide. Maximum desorption of the metal takes place within 5 bed volumes while complete desorption occurs within 10 bed volumes. Details of preparation of the biosorbent, characterization, and adsorption studies are presented. Dominant sorption mechanisms are ionic interactions and complexation.

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Section: Preparation Of Chitosanmentioning

confidence: 99%

Removal of heavy metal from industrial wastewater using chitosan coated oil palm shell charcoal

Nomanbhay¹,

Palanisamy²

2005

Electro Journal of Biotech

330

174

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“…Only β-hydroxy acid 3 and β-keto acid 2 showed significant inhibitory activity regarding the conversion of geranyl diphosphate ( Figure 3). 25 Their IC50 values are 0.36 and 0.58 mM, respectively. At 1 mM concentration, β-hydroxy carboxylate 3 showed almost complete inhibition of ubiA-transferase activity.…”

Section: Ubia-transferase Inhibitionmentioning

confidence: 96%

Synthesis, inhibitory and activation properties of prenyldiphosphate mimics for aromatic prenylations with ubiA-prenyl transferase

Zakharova¹,

Fulhorst²,

Luczak³

et al. 2004

Arkivoc

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4-Hydroxybenzoate oligoprenyl transferase from E. coli (ubiA-prenyl transferase) is a crucial enzyme for ubiquinone biosynthesis. It catalyzes the formation of 3-oligoprenyl-4-hydroxybenzoates like geranyl hydroxybenzoate (GHB, 23) from geranyl pyrophosphate (GPP, 22). Several analogues and mimics of geranyl pyrophosphate have been prepared for an examination of their ability to inhibit the enzyme. 7,11-Dimethyl-3-oxododeca-6,10-dienoic acid (2), 3-hydroxy-7,11-dimethyldodeca-6,10-dienoic acid (3), 2-hydroxy-4,8-dimethyl-3,7-nonadienylphosphonic acid (4), and tripotassium [[(4E)-5,9-dimethyldeca-4,8-dienyl]phosphinato](difluoro)methylphosphonate (5) were synthesized from geraniol. ω-2,ω-1-Dihydroxylated farnesyl diphosphate 6 was prepared from trans,trans-farnesol. All compounds were tested for enzyme inhibition in a competitive assay with natural substrate. The effect of these compounds on ubiA-prenyltransferase activity varied substantially, ranging from almost full inhibition to, surprisingly, enhanced enzymatic activity at low concentrations by some compounds. A special, EDTAmodifyable magnesium effect is discussed as potential reason.

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“…Several physical and chemical methods such as chemical modification [215], immobilization [216], protein engineering [217] and directed evolution [218] have been employed for obtaining enzymes stable in the presence of organic solvents [219,220]. However, if enzymes are naturally stable and exhibit high activities in the presence of organic solvents, the stabilization of enzymes will not be required.…”

Section: Alkaline Proteases From Organic Solvent Tolerant Microbesmentioning

confidence: 99%

Extreme Environments: Goldmine of Industrially Valuable Alkali-stable Proteases

Garg¹,

Singh²

2015

Enz Eng

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Since the advent and release of Bio 40 (the first detergent with bacterial alkaline protease) in 1959, exploration of the microbial alkaline proteases has been exploited beyond expectations. The inventory of microbial alkaline proteases is difficult to draft as it is increasing daily. Most of these proteases are the result of studies in which one or a few isolates were targeted for an alkali-stable enzyme. Although, the worldwide research on microbial alkaline proteases has been widely performed, we still need an improved enzyme capable of catalyzing reactions under extreme conditions (also called as extremozymes), e.g., high alkalinity and salinity, anhydrous environment, cold and hot environment, etc. As the search for extremozymes is in progress, it is imperative to explore the extreme environments to get some novel microbial strains (extremophiles) for alkali-stable proteases. This review article is an effort to compile the scattered information on some extremophiles and their alkali-stable proteases, which may have better specific industrial applications. It includes: (i) various extreme environments relevant to industrial biocatalysts, (ii) strategies of extremophilic microbes and enzymes which make them able to tolerate such conditions, and (iii) an overview of some important work done so far to explore industrially relevant extremophilic enzymes from extremophiles.

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Biocatalysis in nonaqueous solvents

Cited by 142 publications

References 42 publications

Removal of heavy metal from industrial wastewater using chitosan coated oil palm shell charcoal

Removal of heavy metal from industrial wastewater using chitosan coated oil palm shell charcoal

Synthesis, inhibitory and activation properties of prenyldiphosphate mimics for aromatic prenylations with ubiA-prenyl transferase

Extreme Environments: Goldmine of Industrially Valuable Alkali-stable Proteases

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