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Sasithorn Uttatree Pakorn Winayanuwattikun Jittima Charoenpanich 《Applied biochemistry and biotechnology》2010,162(5):1362-1376
The benzene tolerant Acinetobacter baylyi isolated from marine sludge in Angsila, Thailand could constitutively secrete lipolytic enzymes. The enzyme was successfully
purified 21.89-fold to homogeneity by ammonium sulfate precipitation and gel-permeable column chromatography with a relative
molecular mass as 30 kDa. The enzyme expressed maximum activity at 60°C and pH 8.0 with p-nitrophenyl palmitate as a substrate and found to be stable in pH and temperature ranging from 6.0-9.0 to 60-80°C, respectively.
A study on solvent stability revealed that the enzyme was highly resisted to many organic solvents especially benzene and
isoamyl alcohol, but 40% inhibited by decane, hexane, acetonitrile, and short-chain alcohols. Lipase activity was completely
inhibited in the presence of Fe2+, Mn2+, EDTA, SDS, and Triton X-100 while it was suffered detrimentally by Tween 80. The activity was enhanced by phenylmethylsulfonyl
fluoride (PMSF), Na+, and Mg2+ and no significant effect was found in the presence of Ca2+ and Li+. Half of an activity was retained by Ba2+, Ag+, Hg+, Ni2+, Zn2+, and DTT. The enzyme could hydrolyze a wide range of p-nitrophenyl esters, but preferentially medium length acyl chains (C8-C12). Among natural oils and fats, the enzyme 11-folds favorably catalyzed the hydrolysis of rice bran oil, corn oil, sesame
oil, and coconut oil in comparison to palm oil. Moreover, the transesterification activity of palm oil to fatty acid methyl
esters (FAMEs) revealed 31.64 ± 1.58% after 48 h. The characteristics of novel A. baylyi lipase, as high temperature stability, organic solvent tolerance, and transesterification capacity from palm oil to FAMEs,
indicate that it could be a vigorous biocatalyzer in the prospective fields as bioenergy industry or even in organic synthesis
and pharmaceutical industry. 相似文献
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Thanawat Pattananandecha Sutasinee Apichai Sasithorn Sirilun Jakaphun Julsrigival Kasirawat Sawangrat Fumihiko Ogata Naohito Kawasaki Busaban Sirithunyalug Chalermpong Saenjum 《Molecules (Basel, Switzerland)》2021,26(17)
Five glutinous purple rice cultivars and non-glutinous purple rice cultivated in different altitudes in the north of Thailand were collected. The samples were extracted using ethanol and determined for anthocyanins using HPLC. The total phenolic content (TPC), total flavonoid content (TFC), and the antioxidant, anti-inflammatory, and antimicrobial activities against foodborne pathogens were investigated. The highland glutinous cultivar named Khao’ Gam Luem-Phua (KGLP) extract had significantly high levels of cyanidin 3-O-glucoside, peonidin 3-O-glucoside, delphinidin 3-O-glucoside, TPC, and TFC, as well as exerting a potent antioxidant activity through ABTS assay (524.26 ± 4.63 VCEAC, mg l-ascorbic-ascorbic/g extract), lipid peroxidation (IC50 = 19.70 ± 0.31 µg/mL), superoxide anions (IC50 = 11.20 ± 0.25 µg/mL), nitric oxide (IC50 = 17.12 ± 0.56 µg/mL), a suppression effect on nitric oxide (IC50 = 18.32 ± 0.82 µg/mL), and an inducible nitric oxide synthase production (IC50 = 23.43 ± 1.21 µg/mL) in combined lipopolysaccharide-interferon-γ-activated RAW 264.7 murine macrophage cells. Additionally, KGLP also exhibited antimicrobial activity against foodborne pathogens, Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis, and Vibrio parahaemolyticus. These results indicate that Thai glutinous purple rice cultivated on the highland could be a potent natural source of antioxidants, anti-inflammatories, and antimicrobial agents for use as a natural active pharmaceutical ingredient in functional food and nutraceutical products. 相似文献
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The optical properties of Cr3+ ions in lithium metasilicate (Li2O · SiO2) transparent glass-ceramics were investigated. The main crystalline phase precipitated was the lithium metasilicate (Li2O · SiO2) crystal. The percent crystallinity and crystalline size were ranging 65-75% and 20-35 nm, respectively. The color changes drastically to deep pink from emerald green upon crystallization. New and strong absorption bands appeared and the absorption intensity increases by about 10 times that in glass. These new absorption bands are found to be derived from Cr3+ ions in octahedral sites in the lithium metasilicate crystal lattice. Cr3+ ions substitute for three Li+ ions and occupy the distorted octahedral site between single [SiO4]n chains of lithium metasilicate crystal. The ligand field parameters can be estimated: 10Dq = 13 088 cm−1, B = 453 cm−1, Dq/B = 2.89 and C = 2036 cm−1. The near-infrared luminescence centered at 1250 nm was not detected in the deep pink glass-ceramics unlike emerald green glass. 相似文献
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Sasithorn Kongruang Myung Joo Han Claudia Isela Gil Breton Michael H. Penner 《Applied biochemistry and biotechnology》2004,113(1-3):213-231
Methods for the quantification of total and accessible reducing ends on traditional cellulose substrates have been evaluated
because of their relevance to enzyme-catalyzed cellulose saccharification. For example, quantification of accessible reducing
ends is likely to be the most direct measure of substrate concentration for the exo-acting, reducing end-preferring cellobiohydrolases.
Two colorimetric assays (dinitrosalicylic acid [DNS] and bicinchoninic acid [BCA] assay) and a radioisotope approach (NaB3H4 labeling) were evaluated for this application. Cellulose substrates included microcrystalline celluloses, bacterial celluloses,
and filter paper. Estimates of the number of reducing ends per unit mass cellulose were found to be dependent on the assay
system (i.e. the DNS and BCA assays gave strikingly different results). DNS-based values were several-fold higher than those
obtained using the BCA assay, with fold-differences being substrate specific. Sodium borohydride reduction of celluloses,
using cold or radiolabeled reagent under relatively mild conditions, was used to assess the number of surface (solvent-accessible)
reducing ends. The results indicate that 30–40% of the reducing ends on traditional cellulose substrates are not solvent accessible;
that is, they are buried in the interior of cellulose structures and thus not available to exo-acting enzymes. 相似文献
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Bacterial Cellulose Production by Acetobacter xylinum Strains from Agricultural Waste Products 总被引:1,自引:0,他引:1
Kongruang S 《Applied biochemistry and biotechnology》2008,148(1-3):245-256
Bacterial cellulose is a biopolysaccharide produced from the bacteria, Acetobacter xylinum. Static batch fermentations for bacterial cellulose production were studied in coconut and pineapple juices under 30 °C in
5-l fermenters by using three Acetobacter strains: A. xylinum TISTR 998, A. xylinum TISTR 975, and A. xylinum TISTR 893. Experiments were carried out to compare bacterial cellulose yields along with growth kinetic analysis. Results
showed that A. xylinum TISTR 998 produced a bacterial cellulose yield of 553.33 g/l, while A. xylinum TISTR 893 produced 453.33 g/l and A. xylinum TISTR 975 produced 243.33 g/l. In pineapple juice, the yields for A. xylinum TISTR 893, 975, and 998 were 576.66, 546.66, and 520 g/l, respectively. The strain TISTR 998 showed the highest productivity
when using coconut juice. Morphological properties of cellulose pellicles, in terms of texture and color, were also measured,
and the textures were not significantly different among treatments. 相似文献
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