• Mycobiology
• /
• v.47 no.4
• /
• pp.512-520
• /
• 2019

Statistical experimental methods were used to optimize the medium for mass production of a novel laccase3 (Lac3) by recombinant Saccharomyces cerevisiae TYEGLAC3-1. The basic medium was composed of glucose, casamino acids, yeast nitrogen base without amino acids (YNB w/o AA), tryptophan, and adenine. A one-factor-at-a-time approach followed by the fractional factorial design identified galactose, glutamic acid, and ammonium sulfate, as significant carbon, nitrogen, and mineral sources, respectively. The steepest ascent method and response surface methodology (RSM) determined that the optimal medium was (g/L): galactose, 19.16; glutamic acid, 5.0; and YNB w/o AA, 10.46. In this medium, the Lac3 activity (277.04 mU/mL) was 13.5 times higher than that of the basic medium (20.50 mU/mL). The effect of temperature, pH, agitation (rpm), and aeration (vvm) was further examined in a batch fermenter. The best Lac3 activity was 1176.04 mU/mL at 25 ℃, pH 3.5, 100 rpm, and 1 vvm in batch culture.

• Journal of the Korean Electrochemical Society
• /
• v.7 no.2
• /
• pp.83-88
• /
• 2004

[ $DeniLite^{TM}$ ] laccase immobilized Pt electrode was used for amperometric detection of some catechol derivatives and o-aminophenol (OAP) derivative by means of substrate recycling. In case of catechol derivatives, the obtained sensitivities are 85, 79 and $57 nA/{\mu}M$ with linear ranges of $0.6\~30,\;0.6\~30\;and\; 1\~25 {\mu}M$ and detection limits (S/N=3) of 0.2, 0.2 and $0.3{\mu}M$ for 3,4-dihydroxycinnaminic acid (3,4-DHCA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), respectively. In case of OAP derivative, the obtained sensitivity is $237 nA/{\mu}M$ with linear range of $0.2\~15{\mu}M$ and detection limit of 70 nM for 2-amino-4-chlorophenol (2-A-4-CP). The response time $(t_{90\%})$ is about 2 seconds for each substrate and the long-term stability is around 40-50days for catechol derivatives and 30 days for 2-A-4-CP with retaining $80\%$ of initial activity. The optimal pHs of the sensor for these substrates are in the range of 4.5-5.0, which indicates that stability of the enzymatically oxidized product plays a very important role in substrate recycling. The different sensitivity of the sensor for each substrate can be explained by the electronic effect of the sugstituent on the enzymatically oxidized form.

• The Korean Journal of Mycology
• /
• v.40 no.3
• /
• pp.152-158
• /
• 2012

The lignocellulytic enzymes including a-amylase (EC 3.2.1.1), lignin peroxidase (EC 1.11.1.14), laccase (EC 1.10.3.2), xylanase (EC 3.2.1.8), ${\beta}$-xylosidase (EC 3.2.1.37), ${\beta}$-glucosidase (EC 3.2.1.21) and cellulase (EC 3.2.1.4) were extracted from spent mushroom compost (SMC) of Pleurotus eryngii. Different extraction buffers and conditions were tested for optimal recovery of the enzymes. The optimum extraction was shaking incubation (200 rpm) for 2 h at $4^{\circ}C$. ${\alpha}$-Amylase was extracted with the productivity range from 1.20 to 1.6 Unit/SMC g. Cellulase was recovered with the productivity range from 2.10 to 2.80 U/gf. ${\beta}$-glucosidase and ${\beta}$-xylosidase productivities showed lowest recovery producing 0.1 U/g and 0.02 U/g, respectively. The P. eryngii SMCs collected from three different mushroom farms showed different recovery on laccase and xylanse, cellulase. Furthermore, the water extracted SMC was compared to commercial enzymes for its industrial application in decolorization and cellulase activity.

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.4
• /
• pp.46-53
• /
• 2006

This study was to screen white-rot fungi possesing strong lignin degrading enzymes, glucose-1 oxidase (GOD), laccase (LAC) and Mn-peroxidase (MnP), based on their decolorization activity of Remazol Brilliant Blue R (RBBR). In the midst of 20 tested fungi, 9 isolates were shown 4 kinds of activities such as RBBR decolorization, GOD, LAC and MnP. Relatively high active strains were identified as Phlebia radiata, Trametes versicolor, Abortiporus biennis, Gleophyllum odoratum and Cerrena unicolor. In particular, T. versicolor, G. odoratum, and C. unicolor, which have high activities of LAC, were used to confirm the optimal temperature and pH and to evaluate the effect of inducer, 2,5-xylidine on their LAC activity. The optimum temperatures for mycelial growth were $28^{\circ}C$ for T. versicolor and G. odoratum, and $25^{\circ}C$ for C. unicolor. The optimum pH for mycelial growth was 5.5. Three strains showed the increase of LAC enzyme activity by the addition of 2,5-xylidine. T. versicolor had the highest LAC activity of $22,700nkat/{\ell}$, corresponding to 11.3 times, G. odoratum $15,400nkat/{\ell}$, 9 times and C. unicolor $17,330nkat/{\ell}$, 5.5 times higher than those of the control.

• 한국균학회소식:학술대회논문집
• /
• 2009.05a
• /
• pp.51-52
• /
• 2009

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.1
• /
• pp.19-32
• /
• 2013

In this study, outstanding white rot fungi for biodegradation of organosolv lignin were selected on the basis of their ligninolytic enzyme system. Fifteen white rot fungi were evaluated for their ability to decolorize Remazol Brilliant Blue R (RBBR) in SSC and MEB medium, respectively. Six white rot fungi (Ceriporiopsis subvermispora, Ceriporia lacerate, Fomitopsis insularis, Phanerochaete chrysosporium, Polyporus brumalis, and Stereum hirsutum) decolorized RBBR rapidly in SSC medium within 3 days. The protein contents as well as the activities of manganese peroxidase (MnP) and laccase for 6 selected fungi were determined on the SSC medium with and without organosolv lignin. Interestingly, extracellular protein concentrations were determined to relative higher for S. hirsutum and P. chrysosporium in the presence of organosolv lignin than others. On the other hands, each fungus showed a different ligninolytic enzyme pattern. Among them, F. insularis resulted the highest ligninolytic enzyme activities on incubation day 6, indicating of 1,545 U/mg of MnP activity and 1,259 U/mg of laccase activity. In conclusion, $STH^*$ and FOI were considered as outstanding fungi for biodegradation of organosolv lignin, because $STH^*$ showed high extracellular protein contents and ligninolytic enzyme activities over all, and ligninolytic enzyme activities of FOI were the highest among white rot fungi used in this study.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.6
• /
• pp.424-430
• /
• 2012

In this study, laccase activity, rate of weight loss and degree of lignin degradation of pine wood chips were determined during the liquid and solid state incubation with Polyporus brumalis. The results showed that laccase enzyme activity at untreated wood chip was gradually decreased after 20 days, but enzyme activity with wood chip treatment showed 10 times higher than untreated ones at 60 incubation days. Rate of weight losses of pine chip and rate of lignin loss were 23.4% and 6.3% by P. brumalis during 80 incubation days. Gene expression of pblac1 from P. brumalis was 3 times increased under pine chip treatment at 40 incubation days. Consequently, laccase activity of white rot fungi, P. brumalis, was increased at incubation with wood chip and pblac1 gene was important factor of lignin degradation. Therefore, to regulate lignin degrading enzyme gene expression by using the tools of biotechnology will be able to develop superior strains and it will be useful for pretreatment of lignocellulosic biomass at bioethanol production.

• Food Science and Biotechnology
• /
• v.18 no.4
• /
• pp.1027-1029
• /
• 2009

The aim of this research was to study the structural and rheological properties of gels formed by ferulated maize bran arabinoxylans (MBAX) at different concentrations. MBAX was cross-linked by a laccase leading to the formation of dimers and trimers of ferulic acid (di-FA, tri-FA) as covalent cross-link. An increase in MBAX gels elasticity (from 11 to 20 Pa) as well as lower mesh size (from 80 to 48 nm) were obtained by augmenting the MBAX concentration from 2.5 to 3.5%(w/v), respectively, but no increase in di-FA and tri-FA content was obtained (0.03 and 0.014 ${\mu}$g/mg MBAX, respectively).

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.5 s.133
• /
• pp.76-85
• /
• 2005

The degradation of pentachlorophenol (PCP) by lignin degrading fungi was performed. Several fungi, Abortiporus biennis, Cerrena unicolor and Trametes versicolor, were tested to evaluate the inhibitory effect of PCP on their growth. At the extremal concentration of PCP $(500\;{\mu}M)$, only C. unicolor showed relatively fast growth (60% within 14 days) in the comparison to the control culture. In the case of A. biennis and C. unicolor, when initial PCP concentration was $50\;{\mu}M$, about 88.2% and 79.5% of PCP degradation were achieved within 3 days, respectively. When 2,5-xylidine (0.2 mM) was added to the C. unicolor culture, as high as 98% of PCP degradation was achieved within just an hour after its addition. A. biennis removed 44% of PCP at the same condition. PCP was completely disappeared when laccase activities reached to maximum.

• The Korean Journal of Mycology
• /
• v.43 no.3
• /
• pp.165-173
• /
• 2015

Mattirolomyces terfezioides is a type of sweet truffles that predominantly form ectomycorrhizae with Robinia pseudoacacia. It is also worthy of artificial cultivation. This is the first report on characteristics of mycelial growth and enzyme activities of M. terfezioides collected from R. pseudoacacia forest in Korea. M. terfezioides showed the highest mycelial growth when cultured on potato dextrose agar (PDA) at $30^{\circ}C$ or in modified Melin-Norkran's liquid medium (pH 8.0). The biomass of M. terfezioides was higher in liquid medium containing nitrate-nitrogen than ammonium-nitrogen by 1.8 fold. The mycelia of M. terfezioides showed both carboxymethylcellulase and laccase activities on solid media for enzyme screening.