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Showing papers by "Department of Biotechnology published in 2007"


Journal ArticleDOI
TL;DR: In this article, the authors examined the antioxidative properties and total phenolic contents of two varieties of cowpea (Vigna unguiculata) and examined the raw, dry heated and hydrothermal treated samples were extracted with 70% acetone and the extracts were freeze-dried.

444 citations


Journal ArticleDOI
TL;DR: This review will focus on complex mannan structure and the microbial enzyme complex involved in its complete breakdown, mannanase sources, production conditions and their applications in the commercial sector.
Abstract: Microbial mannanases have become biotechnologically important since they target the hydrolysis of complex polysaccharides of plant tissues into simple molecules like manno-oligosaccharides and mannoses The role of mannanases in the paper and pulp industry is well established and recently they have found application in the food and feed technology, coffee extraction, oil drilling and detergent industry Mannanses are enzymes produced mainly from microorganisms but mannanases produced from plants and animals have also been reported Bacterial mannanases are mostly extracellular and can act in a wide range of pH and temperature, though acidic and neutral mannanases are more common This review will focus on complex mannan structure and the microbial enzyme complex involved in its complete breakdown, mannanase sources, production conditions and their applications in the commercial sector The reference to plant and animal mannanases has been made to complete the overview However, the major emphasis of the review is on the microbial mannanases

399 citations


Journal ArticleDOI
TL;DR: Critical information on secretory, plasma membrane penetration and transcellular properties of Tat and PTD is assembled using molecular analysis and available experimental evidences to solve the dilemma of low protein transduction efficiency and target specific delivery of PTD fusion proteins.

184 citations


Journal ArticleDOI
TL;DR: The present review is an update of various methods used for plant genomic DNA isolation, and it epitomizes the various problems faced and the solutions made to contend with them during DNA isolation from plant cells.
Abstract: Isolating quality DNA from tissues/cells presents a variety of problems in particular when plants are used as the source material The specific characteristics of plants like the presence of rigid polysaccharide cell wall, pigments, chemical heterogeneity of secondary metabolites found in diverse species of plants, etc, necessitate special consideration and skill during isolation procedure Until now, numerous protocols have been published for the purpose, but none is found to be universally applicable Various factors starting from the selection of source material to the concentration of metabolites present in the plant decide the course of the isolation procedure The present review is an update of various methods used for plant genomic DNA isolation, and it epitomizes the various problems faced and the solutions made to contend with them during DNA isolation from plant cells

175 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined the antioxidative properties and total phenolic contents of raw and dry heated seed coat of Tamarindus indica and extracted with methanol followed by 70% acetone, after treating with petroleum ether, solvents were removed using rotary vacuum evaporator and the extracts which contain residual moisture were freeze-dried.
Abstract: The antioxidative properties and total phenolic contents of raw and dry heated seed coat of Tamarindus indica were examined. The raw and dry heated samples were extracted with methanol followed by 70% acetone, after treating with petroleum ether, solvents were removed using rotary vacuum evaporator and the extracts which contain residual moisture were freeze-dried, respectively. Methanol extracts for both raw and dry heated seed coat samples contained higher level of total phenolics and tannins than the aqueous acetone extracts. The extracts were screened for their potential antioxidant activities using such as O 2 − , OH , α , α -diphenyl- β -picrylhydrazyl (DPPH ), ABTS + , FRAP and linoleic acid emulsion model systems. At different concentration of respective solvent extracts, the maximum level of superoxide anion radical scavenging activity (79–85%) was observed at 200 μg of both the raw and dry heated seed coat extracts in the reaction mixture. The DPPH radical and ABTS cation radical scavenging activities were well proved with the ferric reducing antioxidant capacity of the extracts. Interestingly, among the extracts, methanol and aqueous acetone extracts of dry heated sample showed the highest hydroxyl radical scavenging activity of 56.6 and 45.7%, respectively. All extracts, exhibited good antioxidant activity (64.5–71.7%) against the linoleic acid emulsion system and the values were lower and higher than the synthetic antioxdiant, BHA and ascorbic acid, respectively.

157 citations


Journal ArticleDOI
TL;DR: Biofilm-associated Candida show uniform resistance to a wide spectrum of antifungal drugs and a combination of different resistance mechanisms is responsible for drug resistance in clinical isolates of Candida species.
Abstract: Pathogenic yeasts from the genus Candida can cause serious infection in humans particularly, in immunocompromised patients and are now recognized as major agents of hospital acquired (nosocomial) infections. In the recent years, there has been a marked increase in the incidence of treatment failures in candidiasis patients receiving long-term antifungal therapy, which has posed a serious problem in its successful use in chemotherapy. Candida cells acquire drug resistance (MDR) during the course of the treatment. The mechanisms of resistance to azole antifungal agents have been elucidated in Candida species and can be mainly categorized as (i) changes in the cell wall or plasma membrane, which lead to impaired drug (azole) uptake; (ii) alterations in the affinity of the drug target Erg11p (lanosterol 14alpha-demethylase) especially to azoles or in the cellular content of Erg11p due to target site mutation or overexpression of the ERG11 gene; and (iii) the efflux of drugs mediated by membrane transport proteins belonging to the ATP-binding cassette (ABC) transporters, namely CDR1 and CDR2 or to the major facilitator superfamily (MFS) transporter, CaMDR1. Many such manifestations are associated with the formation of Candida biofilms including those occurring on devices like indwelling intravascular catheters. Biofilm-associated Candida show uniform resistance to a wide spectrum of antifungal drugs. A combination of different resistance mechanisms is responsible for drug resistance in clinical isolates of Candida species.

145 citations


Journal ArticleDOI
TL;DR: The results obtained suggest that, in addition to their medicinal activities, E. tereticornis can also serve as a natural mosquitocide.

111 citations


Journal ArticleDOI
TL;DR: RT-PCR primers and assays targeting Seg-2 have been developed for rapid identification (within 24 h) of the six European BTV types and show perfect agreement with the results of conventional virus-neutralization methods.
Abstract: Bluetongue virus (BTV) is the causative agent of bluetongue, a disease of ruminant livestock that occurs almost worldwide between latitudes 3 degrees S and 5 degrees N. There are 24 serotypes of BTV (currently identified by serum neutralization assays). Since 1998, eight strains of six BTV serotypes (1, 2, 4, 8, 9 and 16) have invaded Europe. The most variable BTV protein is major outer-capsid component VP2, encoded by segment 2 (Seg-2) of the double-stranded RNA virus genome. VP2 represents the major target for neutralizing (and protective) antibodies that are generated in response to BTV infection, and is therefore the primary determinant of virus serotype. RT-PCR primers and assays targeting Seg-2 have been developed for rapid identification (within 24 h) of the six European BTV types. These assays are sensitive, specific and show perfect agreement with the results of conventional virus-neutralization methods. Previous studies have identified sequence variations in individual BTV genome segments that allow different isolates to be grouped on the basis of their geographical origins (topotypes). The assays described in this paper can detect any of the BTV isolates of the homologous serotype that were tested from different geographical origins (different Seg-2 topotypes). Primers were also identified that could be used to distinguish members of these different Seg-2 topotypes, as well as field and vaccine strains of most of the European BTV serotypes. The serotype-specific assays (and primers) showed no cross-amplification when they were evaluated with multiple isolates of the most closely related BTV types or with reference strains of the remaining 24 serotypes. Primers developed in this study will be updated periodically to maintain their relevance to current BTV distribution and epidemiology (http://www.iah.bbsrc.ac.uk/dsRNA_virus_proteins/ReoID/rt-pcr-primers.htm).

105 citations


Journal ArticleDOI
TL;DR: The effect of miltefosine in arsenite-resistant Leishmania donovani (Ld-As20) promastigotes displaying an MDR phenotype and overexpressing Pgp-like protein was investigated and results indicate that Ld- as20 is sensitive to milteFosine.

99 citations


Journal ArticleDOI
TL;DR: The n-hexane, ethyl acetate, methanol, and acetone extracts of Piper cubeba Linn and P. retrofractum were evaluated in vitro against promastigotes of Leishmania donovani, and all exhibited significant in vitro activity at 100 μg/ml.
Abstract: The n-hexane, ethyl acetate, methanol, and acetone extracts of Piper cubeba Linn. and P. retrofractum Vahl. (Piperaceae) were evaluated in vitro against promastigotes of Leishmania donovani, and all exhibited significant in vitro activity at 100 μg/ml. Two lignans, cubebin and hinokinin, were isolated from the hexane extract of P. cubeba; and one bis-epoxy lignan, (−)-sesamin, and two amides, pellitorine and piplartine, were isolated from the hexane and methanol extracts of P. retrofractum. Cubebin and piplartine showed significant antileishmanial activity in vitro at 100 μM and were further tested in vivo in a hamster model of visceral leishmaniasis. Piplartine showed activity at 30 mg/kg dose. This is the first report of antileishmanial activity of these two plants and their isolated constituents.

96 citations


Journal ArticleDOI
TL;DR: Of the attempted treatments, autoclaving appeared to be most effective in reducing levels of all the investigated antinutrients, except phytic acid, and also improved the in vitro protein digestibility of B. purpurea seeds.

Journal ArticleDOI
TL;DR: The mass production of tropane alkaloids from adventitious root cultures of Scopolia parviflora, in small-scale bubble column bioreactor (BCB) was attempted and elicitation by Staphylococus aureus increased the specific compound of scopolamine, while the production of hyoscyamine was slightly inhibited in BCB cultures.

Journal ArticleDOI
TL;DR: A multi-prong strategy including primer modifications, various DMSO-betaine combinations and high denaturing temperature conditions was pursued during cDNA synthesis to achieve optimal PCR amplification of templates with high GC content.


Journal ArticleDOI
TL;DR: Penaeus monodon postlarvae were fed with different percentages (0, 25, 50, 75% and 100%) of the herbal appetizer Zingiber officinalis enriched Artemia and a very positive result was found in Z. Officinalis-enriched Artemia-fed postlarva.
Abstract: Penaeus monodon postlarvae were fed with different percentages (0%, 25%, 50%, 75% and 100%) of the herbal appetizer Zingiber officinalis enriched Artemia. After 30 days of culture (i.e. PL-1-30), a very positive result was found in Z. officinalis-enriched Artemia-fed postlarvae. The unenriched Artemia-fed postlarvae consumed 91.0 mg/animal/30 days of feed, whereas the Z. officinalis-enriched Artemia increased their consumption to 127.9 mg/animal/30 days. A similar pattern was noticed in feed absorbed (110.2 mg), dry weight growth (26.7 mg) and feed catabolized (83.2 mg) in Z. officinalis-enriched Artemia because of enzymatic activities. The conversion efficiency of unenriched postlarva was 17.19%, whereas in 100% Z. officinalis-enriched Artemia, the maximum conversion efficiency was 20.85%. The net production efficiency increased significantly (P < 0.05) to 22% from that of the unenriched Artemia-fed postlarvae. The administration of Z. officinalis in all levels produced significantly (P < 0.05) higher weight gain and specific growth rate. The utilization efficiency of feed increased proportionately to the percentages of Z. officinalis. Digestive enzyme activity (amylase, protease and lipase) increased significantly (P < 0.05) in the 50%, 75% and 100% enrichment. Among the different percentages of enrichment, the 100% Z. officinalis-enriched Artemia-fed postlarvae performed better in the overall status.

Journal ArticleDOI
TL;DR: There is strong evidence that the modulation of FAK level regulates the insulin sensitivity of skeletal muscle cells, and a direct role ofFAK in insulin-resistant skeletal muscles cells for the first time is demonstrated.
Abstract: Aims/hypothesis On the basis of our previous studies, we investigated the possible role of focal adhesion kinase (FAK) in the development of insulin resistance in skeletal muscle, a major organ responsible for insulin-stimulated glucose uptake.

Journal ArticleDOI
TL;DR: The results of the present study suggest that ginger might be useful as a potential antitumour agent.
Abstract: Ginger (Zingiber officinale Roscoe, Zingiberaceae) is a commonly used medicinal herb throughout the world. Although some studies have demonstrated its antitumour activities on cancer cells in vitro and in vivo, the exact mechanism is not fully elucidated. Hence, the present study was designed to examine the in vitro cytotoxic activities of saline extract prepared from ginger extract on HEp-2 cell line. The cytotoxic effect of the drug was confirmed by 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and cell counting and estimation of protein, DNA and RNA. Meanwhile, propidium iodide staining and agarose gel electrophoresis were performed for determining the induction of apoptosis. In addition, superoxide radical generation, nitrite formation and glutathione studies show involvement of free radicals. The present results show that the extract exerts dose-dependent suppression of cell proliferation; the IC(50) value was found to be 900 microg/ml. At a dose of 250 microg/ml, marked morphological changes including cell shrinkage and condensation of chromosomes were observed. Agarose gel electrophoresis of DNA from HEp-2 cells treated with 250 microg/ml ginger powder for 24 hr showed marked DNA ladder pattern. The involvement of free radicals was confirmed by increased superoxide production, decreased nitrate formation and depletion of glutathione in ginger-treated cells. Further screening of active components using gas chromatography-mass spectrometry analyses showed the presence of clavatol, geraniol and pinostrobin in the extract. The results of the present study suggest that ginger might be useful as a potential antitumour agent.

Journal Article
TL;DR: The results when compared with the standard drug silymarin revealed that the hepatoprotective activity of the constituent ursolic acid is significant as similar to the standardDrug.
Abstract: The ethanol extract of C. serratum roots and ursolic acid isolated from it were evaluated for hepatoprotective activity against carbon tetrachloride induced toxicity in male Wistar strain rats. The parameters studied were estimation of liver function serum markers such as serum total bilirubin, total protein, alanine transaminase, aspartate transaminase and alkaline phosphatase activities. The ursolic acid showed more significant hepatoprotective activity than crude extract. The histological profile of the liver tissue of the root extract and ursolic acid treated animal showed the presence of normal hepatic cords, absence of necrosis and fatty infiltration as similar to the controls. The results when compared with the standard drug silymarin, revealed that the hepatoprotective activity of the constituent ursolic acid is significant as similar to the standard drug.


Journal ArticleDOI
TL;DR: Phenotypic observations and biochemical analysis showed that altered expression of PPARγ inhibited the formation of myotubes, as well as expression of muscle-specific myogenic proteins including myogenin, MyoD and creatine kinase activity.
Abstract: Peroxisome proliferator-activated receptor gamma (PPARgamma) is a member of the nuclear receptor superfamily known to regulate adipocyte differentiation. However, its role in skeletal muscle differentiation is not known. To investigate possible involvement of PPARgamma in skeletal muscle differentiation, we modulated its expression in C2C12 mouse skeletal muscle cells by stable transfection with sense or antisense plasmid constructs of PPARgamma cDNA. Phenotypic observations and biochemical analysis of different myogenic markers showed that altered expression of PPARgamma inhibited the formation of myotubes, as well as expression of muscle-specific myogenic proteins including myogenin, MyoD and creatine kinase activity. Together, we show that critical expression of PPARgamma is required for skeletal muscle cells differentiation.

Journal ArticleDOI
TL;DR: The treatment of promastigotes at drug concentrations inhibiting 50% of topo II activity inflicted a regulated cell death sharing several apoptotic features like externalization of phosphatidylserine, loss of mitochondrial membrane potential, cytochrome C release into the cytosol, activation of cellular proteases and DNA fragmentation.

Journal ArticleDOI
TL;DR: Three different regeneration systems, viz. direct regeneration of adventitious shoot buds from explant, regeneration through callus cultures and somatic embryos were compared to see their effect on transfer of neomycin phosphotransferase and β-glucuronidase, and stable integration of transgenes with two to four copy numbers were confirmed.
Abstract: Three different regeneration systems, viz. direct regeneration of adventitious shoot buds from explant, regeneration through callus cultures and somatic embryos were compared to see their effect on transfer of neomycin phosphotransferase (nptII) and β-glucuronidase (GUS) reporter gene (gus) to Morus alba clone M5, through Agrobacterium tumefaciens mediated transformation. Pre-conditioning and co-cultivation durations had a marked effect on transformation frequency. The highest transformation frequency of 18.6% was obtained using direct induction of adventitious shoot buds. Expression and presence of transgene were assayed histochemically and through polymerase chain reaction. Southern analysis of GUS and PCR positive transformants confirmed stable integration of transgenes with two to four copy numbers. The selected transformants showed normal phenotype under in vitro and field conditions.

Journal ArticleDOI
TL;DR: Leptin downregulated the secretion of tumor necrosis factor-alpha (TNF-alpha) by ethanol-induced HepG2 cells and could be useful in preventing the damage produced by ethanol, which might be of therapeutic interest.

Journal ArticleDOI
TL;DR: The proteomic studies, although, tend to be analytical in nature, yet many strategies of preparative protein purification can be usefully employed in such studies, and the importance of purification techniques which are capable of dealing with samples which are suspensions rather than clear solution is pointed out.

Journal ArticleDOI
TL;DR: The occurrence of C. parvum, in nearly one third of cases in the present series indicates that the zoonotic transmission is of considerable significance in the epidemiology of Cryptosporidiosis in the study area.

Book ChapterDOI
01 Jan 2007
TL;DR: This chapter discusses alternate solvents that help in making a chemical reaction green, including use of safer solvent and water as solvent, solvent-free conditions, supercritical water, and room temperature ionic liquids.
Abstract: Publisher Summary This chapter discusses alternate solvents that help in making a chemical reaction green. In order to move towards green chemistry, it is essential to avoid the use of organic solvents for the reaction media. At the heart of green chemistry are alternative reaction media. They are the basis of many of the cleaner chemical technologies that have reached commercial development. The chapter describes some of the most well known among these alternate reaction media. This includes use of safer solvents and water as solvent, solvent-free conditions, supercritical water, and room temperature ionic liquids. These are explained with relevant illustrative figures. To achieve near-total “greenness” of chemical processes, it is important to focus on every aspect of the chemical reaction. For this, solvents that serve as catalysts should be employed. The chemists should use solvents that can be easily separated downstream. In addition, recyclable reagents that are effective in catalytic concentrations should be used. Lastly, biodegradable solvents and reagents should be employed for chemical reactions.

Journal ArticleDOI
TL;DR: Administration of either APT or AHMP along with the major anti-leukemic drug 6MP might serve as a good combination cancer chemotherapy regimen because the efficiency of substrate binding to XOD and its subsequent catalytic hydroxylation is much superior for xanthine in comparison to 6MP.
Abstract: The anticancer drug, 6-mercaptopurine (6MP) is subjected to metabolic clearance through xanthine oxidase (XOD) mediated hydroxylation, producing 6-thiouric acid (6TUA), which is excreted in urine. This reduces the effective amount of drug available for therapeutic efficacy. Co-administration of allopurinol, a suicide inhibitor of XOD, which blocks the hydroxylation of 6MP inadvertently enhances the 6MP blood level, counters this reduction. However, allopurinol also blocks the hydroxylation of hypoxanthine, xanthine (released from dead cancer cells) leading to their accumulation in the body causing biochemical complications such as xanthine nephropathy. This necessitates the use of a preferential XOD inhibitor that selectively inhibits 6MP transformation, but leaves xanthine metabolism unaffected. Here, we have characterized two such unique inhibitors namely, 2-amino-6-hydroxy-8-mercaptopurine (AHMP) and 2-amino-6-purinethiol (APT) on the basis of IC50 values, residual activity in bi-substrate simulative reaction and the kinetic parameters like Km, Ki, kcat. The IC50 values of AHMP for xanthine and 6MP as substrate are 17.71 ± 0.29 μM and 0.54 ± 0.01 μM, respectively and the IC50 values of APT for xanthine and 6MP as substrates are 16.38 ± 0.21 μM and 2.57 ± 0.08 μM, respectively. The Ki values of XOD using AHMP as inhibitor with xanthine and 6MP as substrate are 5.78 ± 0.48 μM and 0.96 ± 0.01 μM, respectively. The K i values of XOD using APT as inhibitor with xanthine and 6MP as substrate are 6.61 ± 0.28 μM and 1.30 ± 0.09 μM. The corresponding Km values of XOD using xanthine and 6MP as substrate are 2.65 ± 0.02 μM and 6.01 ± 0.03 μM, respectively. The results suggest that the efficiency of substrate binding to XOD and its subsequent catalytic hydroxylation is much superior for xanthine in comparison to 6MP. In addition, the efficiency of the inhibitor binding to XOD is much more superior when 6MP is the substrate instead of xanthine. We further undertook the toxicological evaluation of these inhibitors in a single dose acute toxicity study in mice and our preliminary experimental results suggested that the inhibitors were equally non-toxic in the tested doses. We conclude that administration of either APT or AHMP along with the major anti-leukemic drug 6MP might serve as a good combination cancer chemotherapy regimen.

Journal Article
TL;DR: Plantlets from two--stage rooting procedure showed more rapid growth and satisfactory survival during hardening of plants and on transfer to field, and reduced rooting in continuous light treatment showed reduced rooting.
Abstract: Shoots of apple rootstocks raised in vitro were transferred to various rooting media to study the effect of different factors on root initiation and development. Various concentrations of indole-3-butyric acid (IBA) initiated rooting but maximum rooting percentage was found with 2.0 and 2.5 mg 1 -1 of IBA in M7 and with 1.0 mg 1 -1 of IBA in MM106. The drawback was that the roots were thick, short and with profuse callus. The presence of activated charcoal (AC) in the rooting medium improved the rooting quality but reduced the rooting percentage in both the rootstocks. In high auxin dip of 70, 80 and 90 mg 1 -1 IBA for 2, 2 and 1 hr showed 75-85 per cent rooting in M7, but lacked reproducibility of the results. Whereas in MM106, 66 - 70 % rooting was achieved with 70 mg 1 -1 of IBA dip for 3 h. Root induction in shoots in IBA containing liquid medium (LM) in dark for few days and root elongation in IBA - free medium in light proved most effective. On the other hand, continuous light treatment showed reduced rooting. Reduction of MS salts and sucrose in root elongation medium showed decreased rooting. Plantlets from two - stage rooting procedure showed more rapid growth and satisfactory survival during hardening of plants and on transfer to field.

Journal ArticleDOI
TL;DR: Ionically bound peroxidases (POD) were salt extracted from the pulp of four Indian apple varieties, i.e., Golden delicious HP, Golden delicious JK, Red delicious, and Royal delicious and showed thermostability at 60°C, while three other per oxidases were observed at 50°C.
Abstract: Ionically bound peroxidases (POD) were salt extracted from the pulp of four Indian apple varieties, i.e., Golden delicious HP, Golden delicious JK, Red delicious, and Royal delicious. They were precipitated with chilled ethanol. Thermal treatments of partially purified enzymes were given from 40-70 degrees C for 30 minutes. Golden delicious HP peroxidase showed thermostability at 60 degrees C, while three other peroxidases were observed at 50 degrees C. Phenolic compounds (i.e., caffeic acid, ferulic acids, p-coumaric acid, protocatechuic acid) and metal ions (i.e., Cu2+ and Fe2+) activated all apple peroxidases. However, Mn2+ inhibited the peroxidases from Golden delicious HP, Golden delicious JK, and Red delicious, and a substantial increase was observed in Royal delicious peroxidase. Mg2+ inhibited the peroxidases from Golden delicious HP and Red delicious, but marginal activation was reported in peroxidases from Golden delicious JK and Royal delicious. Zn2+ established stimulation in Golden delicious HP and Golden delicious JK peroxidases, but inhibition was observed in peroxidases in Red delicious and Royal delicious.. Methionine, proline, tryptophan, and valine stimulated all four apple peroxidases, but cysteine showed inhibition in Golden delicious JK.

Journal ArticleDOI
TL;DR: A purified alkaline thermoalkalophilic extracellular lipase of Pseudomonas aeruginosa MTCC-4713 was efficiently immobilized onto a synthetic poly(AAc-co-HPMA-cl-EGDMA) hydrogel by adsorption and the bound lipase was evaluated for its hydrolytic potential towards various p-nitrophenyl acyl esters varying in their C-chain lengths.
Abstract: Microbial lipases (E.C. 3.1.1.3) are preferred biocatalysts for the synthesis of esters in organic solvents. Various extracellular thermoalkaliphilic lipases have been reported from Pseudomonas sp. In the present study, a purified alkaline thermoalkalophilic extracellular lipase of Pseudomonas aeruginosa MTCC-4713 was efficiently immobilized onto a synthetic poly(AAc-co-HPMA-cl-EGDMA) hydrogel by adsorption and the bound lipase was evaluated for its hydrolytic potential towards various p-nitrophenyl acyl esters varying in their C-chain lengths. The bound lipase showed optimal hydrolytic activity towards p-nitrophenyl palmitate (p-NPP) at pH 8.5 and temperature 45°C. The hydrolytic activity of the hydrogel-bound lipase was markedly enhanced by the presence of Hg2+, Fe3+, and NH salt ions in that order. The hydrogel-immobilized lipase (25 mg) was used to perform esterification in various n-alkane(s) that resulted in ∼ 84.9 mM of methyl acrylate at 45°C in n-heptane under shaking (120 rpm) after 6 h, when methanol and acrylic acid were used in a ratio of 100 mM:100 mM, respectively. Addition of a molecular sieve (3A × 1.5 mm) to the reaction system at a concentration of 100 mg/reaction vol (1 mL) resulted in a moderate enhancement in conversion of reactants into methyl acrylate (85.6 mM). During the repetitive esterification under optimum conditions, the hydrogel-bound lipase produced 71.3 mM of ester after 10th cycle of reuse. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 183–191, 2007