Characterization of alkaliphilic laccase activity in the culture supernatant of<i>Myrothecium verrucaria</i>24G-4 in comparison with bilirubin oxidase

Sulistyaningdyah, Woro Triarsi; Ogawa, Jun; Tanaka, Hiromi; Maeda, Chihiro; Shimizu, Sakayu

doi:10.1016/s0378-1097(03)00892-9

Cited by 64 publications

(40 citation statements)

References 15 publications

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“…The filtrate was analysed for activities of lignin peroxidase (LiP) (Archibald 1992), manganese peroxidase (MnP) (Buswell et al 1995) laccase (Lac) and vanillyl alcohol oxidase (VAO) (Jacques et al 1998). Lac activity was measured using different substrates, including ABTS (Buswell et al 1995), guaiacol (Trejo-Hernandez et al 2001, 4-aminoantipyrine (Sulistyaningdyah et al 2004), 2,6-dimethoxyphenol (Slomczynski et al 1995) and syringaldazine (Criquet et al 1999). LiP unit activity was defined as the amount of enzyme required to catalyze 0.1 absorbance decrease per minute.…”

Section: Sampling Extraction and Analytical Methodsmentioning

confidence: 99%

Laccase activities of a soil fungus Penicillium simplicissimum in relation to lignin degradation

Zeng

Huang

et al. 2006

World J Microbiol Biotechnol

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The laccase activities of Penicillium simplicissimum H5 during solid-state fermentation with rice straw were studied. Degradation of lignocellulose was also followed. Results showed that all supplemental carbon sources inhibited the laccase activity in different degrees, while suitable concentrations of supplemental nitrogen sources remarkably enhanced the laccase activity. The enhancement of activity by the ordinary laccase inducers 2, 2¢-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and xylidine was not observed in this study. Lignocellulose degradation was improved when laccase activity was relatively low, suggesting a polymerizing function of laccase in lignin degradation by P. simplicissimum.

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Section: Sampling Extraction and Analytical Methodsmentioning

confidence: 99%

Laccase activities of a soil fungus Penicillium simplicissimum in relation to lignin degradation

Zeng

Huang

et al. 2006

World J Microbiol Biotechnol

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“…Fungal laccases are often active at acidic pH and low ionic strengths, where the proteins are much less stable [7]. Thus, recent efforts have been directed both towards identifying new alkalophilic and halophilic laccases [8]–[12], and towards improving the alkalophilicity of fungal laccases by e.g. directed evolution [7].…”

Section: Introductionmentioning

confidence: 99%

Characterization of an Alkali- and Halide-Resistant Laccase Expressed in E. coli: CotA from Bacillus clausii

2014

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The limitations of fungal laccases at higher pH and salt concentrations have intensified the search for new extremophilic bacterial laccases. We report the cloning, expression, and characterization of the bacterial cotA from Bacillus clausii, a supposed alkalophilic ortholog of cotA from B. subtilis. Both laccases were expressed in E. coli strain BL21(DE3) and characterized fully in parallel for strict benchmarking. We report activity on ABTS, SGZ, DMP, caffeic acid, promazine, phenyl hydrazine, tannic acid, and bilirubin at variable pH. Whereas ABTS, promazine, and phenyl hydrazine activities vs. pH were similar, the activity of B. clausii cotA was shifted upwards by ∼0.5–2 pH units for the simple phenolic substrates DMP, SGZ, and caffeic acid. This shift is not due to substrate affinity (KM) but to pH dependence of catalytic turnover: The kcat of B. clausii cotA was 1 s−1 at pH 6 and 5 s−1 at pH 8 in contrast to 6 s−1 at pH 6 and 2 s−1 at pH 8 for of B. subtilis cotA. Overall, kcat/KM was 10-fold higher for B. subtilis cotA at pHopt. While both proteins were heat activated, activation increased with pH and was larger in cotA from B. clausii. NaCl inhibited activity at acidic pH, but not up to 500–700 mM NaCl in alkaline pH, a further advantage of the alkali regime in laccase applications. The B. clausii cotA had ∼20 minutes half-life at 80°C, less than the ∼50 minutes at 80°C for cotA from B. subtilis. While cotA from B. subtilis had optimal stability at pH∼8, the cotA from B. clausii displayed higher combined salt- and alkali-resistance. This resistance is possibly caused by two substitutions (S427Q and V110E) that could repel anions to reduce anion-copper interactions at the expense of catalytic proficiency, a trade-off of potential relevance to laccase optimization.

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“…It is known that BOD oxidizes some laccase substrates (20,22); however, laccase, ascorbate oxidase, and ceruloplasmin show little or no BOD activity (1,21), though one exception is the alkaliphilic laccase from Myrothecium verrucaria 24G-4 (18). It has been proposed that these differences in substrate specificity reflect the heterogeneity of the amino acid sequences within the consensus domains (8).…”

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confidence: 99%

Bilirubin Oxidase Activity of Bacillus subtilis CotA

Sakasegawa

Ishikawa

Imamura

et al. 2006

Appl Environ Microbiol

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Characterization of alkaliphilic laccase activity in the culture supernatant ofMyrothecium verrucaria24G-4 in comparison with bilirubin oxidase

Cited by 64 publications

References 15 publications

Laccase activities of a soil fungus Penicillium simplicissimum in relation to lignin degradation

Laccase activities of a soil fungus Penicillium simplicissimum in relation to lignin degradation

Characterization of an Alkali- and Halide-Resistant Laccase Expressed in E. coli: CotA from Bacillus clausii

Bilirubin Oxidase Activity of Bacillus subtilis CotA

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