pH-controlled regioselective nucleophilic ring-opening of epoxide: an improved process for the preparation of (R)-(-)- or (S)-(+)-3-hydroxytetrahydrofuran.

An environmentally benign, cost-effective and scalable process for the preparation of both the enantiomers of 3-hydroxytetrahydrofuran has been developed. pH-Controlled ring opening of enantiomerically pure epichlorohydrins with cyanohydrin is the key step of the process. The entire protocol does not require any column purification.

Bioconversion of Iminodiacetonitrile to Iminodiacetic acid with whole cells of Lysinibacillus boronitolerans MTCC 107614 (IICT-akl252).

Biotechnological potential of nitrilases are prompting significant interest in finding the novel microbes capable of hydrolyzing nitriles. In this view, we have screened about 450 bacterial strains for nitrilase production using bioconversion of iminodiacetonitrile (IDAN) to iminodiacetic acid (IDA) through hydrolysis and obtained six nitrilase-producing isolates. Among these six isolates, IICT-akl252 was promising which was identified as Lysinibacillus boronitolerans. This is the first report on L. boronitolerans for nitrilase activity. Optimization of various medium and reaction parameters for maximizing the nitrilase production using whole cells in shake flask was carried out for L. boronitolerans IICT-akl252. Sucrose (2 %) as a carbon source attained better nitrilase yield while IDAN appeared to be the preferable inducer (0.2 %). The maximum IDA formation was achieved with 100 mM IDAN and 150 mg/ml cells at 30 °C and pH 6.5. After optimization of the culture and reaction conditions, the activity of nitrilase was increased by 2.3-fold from 27.2 to 64.5 U. The enzyme was stable up to 1 h at 50 °C. The enzyme was able to hydrolyze aliphatic, aromatic and heterocyclic nitrile substrates.

Optimization of nitrilase production from Alcaligenes faecalis MTCC 10757 (IICT-A3): effect of inducers on substrate specificity.

Microbial nitrilases are biocatalysts of interest and the enzyme produced using various inducers exhibits altered substrate specificity, which is of great interest in bioprocess development. The aim of the present study is to investigate the nitrilase-producing Alcaligenes faecalis MTCC 10757 (IICT-A3) for its ability to transform various nitriles in the presence of different inducers after optimization of various parameters for maximum enzyme production and activity. The production of A. faecalis MTCC 10757 (IICT-A3) nitrilase was optimum with glucose (1.0%), acrylonitrile (0.1%) at pH 7.0. The nitrilase activity of A. faecalis MTCC 10757 (IICT-A3) was optimum at 35 °C, pH 8.0 and the enzyme was stable up to 6 h at 50 °C. The nitrilase enzyme produced using different inducers was investigated for substrate specificity. The enzyme hydrolyzed aliphatic, heterocyclic and aromatic nitriles with different substitutions. Acrylonitrile was the most preferred substrate (~40 U) as well as inducer. Benzonitrile was hydrolyzed with almost twofold higher relative activity than acrylonitrile when it was used as an inducer. The versatile nitrilase-producing A. faecalis MTCC 10757 (IICT-A3) exhibits efficient conversion of both aliphatic and aromatic nitriles. The aromatic nitriles, which show not much or no affinity towards nitrilase from A. faecalis, are hydrolyzed effectively with this nitrilase-producing organism. Studies are in progress to exploit this organism for synthesis of industrially important compounds.

Relevance of Frank's solvent classification as typically aqueous and typically non-aqueous to activities of firefly luciferase, alcohol dehydrogenase, and alpha-chymotrypsin in aqueous binaries.

Effects of cosolvent concentration on activity of fire fly luciferase, alpha-chymotrypsin, and alcohol dehydrogenase from baker's yeast (Saccharomyces cerevisiae) have been studied for several solvents with varying hydrophobicities (logP from +1.0 to -1.65) and polarities (dielectric constant from 7.4 to 109). The inhibitory effect of the cosolvent is examined in light of Frank's classification of solvents into 'typically aqueous (TA)' and 'typically non-aqueous (TNA).' The solvent concentration at which the enzyme activity decreases to half, the C(50) values, for TA solvents such as 1-cyclohexyl-2-pyrrolidinone, 2-butoxyethanol, 1-methyl-2-pyrrolidinone, tetrahydrofuran, t-butanol, and ethanol correlate quite well with their critical hydrophobic interaction concentration, rather than logP, while those for TNA solvents such as acetonitrile, dimethyl formamide, formamide, and dimethyl sulfoxide correlate well with logP. The interactions of TA solvents with proteins appear to be governed mainly by hydrophobic interactions while both hydrophobic and hydrophilic interactions play important role in case of TNA solvents.

Gelatin blends with alginate: gels for lipase immobilization and purification.

Blends of natural polysaccharide sodium alginate (5%) with gelatin (3%) cross-linked with glutaraldehyde provide beads with excellent compressive strength (8 x 10(4) Pa) and regular structure on treatment with calcium chloride. Lipases from porcine pancreas, Pseudomonas cepacia, and Candida rugosa were immobilized in such a blend with excellent efficiency. The immobilized enzymes were stable and were reused several times without significant loss of enzyme activity both in aqueous and reverse micellar media. The beads were functionalized with succinic anhydride to obtain beads with extra carboxylic acid groups. These functionalized beads were then successfully used for 7.4-fold purification of crude porcine pancreatic lipase in a simple operation of protein binding at pH 5 and release at pH 8.5.