scholarly journals Heterologous expression of Stlac2, a laccase isozyme of Setosphearia turcica, and the ability of decolorization of malachite green

2019 ◽  
Author(s):  
Ning Liu ◽  
Shen Shen ◽  
Hui Jia ◽  
Beibei Yang ◽  
Xiaoyue Guo ◽  
...  

AbstractLaccases can catalyze monoelectronic oxidation and have shown to have an increasing value in industrial application. In this study, as identified by Native-PAGE and ESI-MS/MS, ascomycetous fungus Setosphaeria turcica produced three laccase isozymes: Stlac1, Stlac2, and Stlac6. Stlac2 was heterologously expressed in both eukaryotic and prokaryotic expression systems. The eukaryotic recombinant Stlac2 expressed in Pichia pastoris was inactive, and also showed a higher molecular weight than predicted because of glycosylation. The depression of laccase activity was attributable to the incorrect glycosylation at Asn97. Stlac2 expressed in Escherichia coli and after being renaturated from the inclusion body, the recombinant Stlac2 exhibited activity of 28.23 U/mg with 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as the substrate. The highest activity was observed at pH of 4.5 and the temperature of 60 °C. The activity of recombinant Stlac2 was inhibited by 10 mM Na+, Mg2+, Ca2+, Mn2+, and increased by 10 mM of Fe3+ with a relatively activity of 315% compared with no addition. Cu2+ did not affect enzyme activity. Recombinant Stlac2 was capable of decolorizing 67.08% of 20 mg/L malachite green in 15 min without any mediators. It is suggested that Stlac2 has potential industrial applications.ImportanceSetosphaeria turcica, an ascomycetous fungus causes northern corn leaf blight, product three laccase isozymes identified by Native-PAGE and ESI-MS/MS. The major expression laccase gene StLAC2 was expression in both eukaryotic and prokaryotic expression systems, which found incorrect glycosylation at Asn97 may result in the depression of laccase activity. The heterologous laccase Stlac2 decolorize organic dye malachite green, which had a potential industrial application.


AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanhua Yao ◽  
Guimei Zhou ◽  
Yonghui Lin ◽  
Xinqi Xu ◽  
Jie Yang

Abstract Laccases are a class of multi-copper oxidases with important industrial values. A thermotolerant laccase produced by a basidiomycete fungal strain Cerrena unicolor CGMCC 5.1011 was studied. With glycerin and peptone as the carbon and nitrogen sources, respectively, a maximal laccase activity of 121.7 U/mL was attained after cultivation in the shaking flask for 15 days. Transcriptomics analysis revealed an expressed laccase gene family of 12 members in C. unicolor strain CGMCC 5.1011, and the gene and cDNA sequences were cloned. A glycosylated laccase was purified from the fermentation broth of Cerrena unicolor CGMCC 5.1011 and corresponded to Lac2 based on MALDI-TOF MS/MS identification. Lac2 was stable at pH 5.0 and above, and was resistant to organic solvents. Lac2 displayed remarkable thermostability, with half-life time of 1.67 h at 70 ºC. Consistently, Lac2 was able to completely decolorize malachite green (MG) at high temperatures, whereas Lac7 from Cerrena sp. HYB07 resulted in accumulation of colored MG transformation intermediates. Molecular dynamics simulation of Lac2 was conducted, and possible mechanisms underlying Lac2 thermostability were discussed. The robustness of C. unicolor CGMCC 5.1011 laccase would not only be useful for industrial applications, but also provide a template for future work to develop thermostable laccases.



2019 ◽  
Vol 8 (3) ◽  
pp. 7240-7243

If we compare wireless communication over wired communication, wireless communication offer more advantages when compared to wired communication such as lower cost, fast deployment, higher flexibility & scalability and mobile nature of system communicated wirelessly. In Industrial automation, industrial communication has very challenging requirements like packet deadline, low transmission jitter, etc. In some places wired communication is only accepted and it cannot be replaced by wireless communication. Industrial applications also run more flexible requirements applications such as email, Video content or any other application. Those services are known as Best Effort (BE) services. In order to do both the industrial application and BE services we have proposed Zigbee communication together with the IEEE 802.11 standard in this article along with comparison between the two standards using physical layer solutions. This Zigbee communication is performed using a industrial automation design and it leads to less power consumption. Result and analysis in terms of real time services is left as a future work in this paper. It is proposed that through Zigbee solution it is possible to obtain better result in certain cases than those achieved using IEEE 802.11 standards.



2018 ◽  
Vol 19 (10) ◽  
pp. 2989 ◽  
Author(s):  
Ji Zhang ◽  
Fuying Ma ◽  
Xiaoyu Zhang ◽  
Anli Geng

Laccases have great potential for industrial applications due to their green catalytic properties and broad substrate specificities, and various studies have attempted to improve the catalytic performance of these enzymes. Here, to the best of our knowledge, we firstly report the directed evolution of a homodimeric laccase from Cerrena unicolor BBP6 fused with α-factor prepro-leader that was engineered through random mutagenesis followed by in vivo assembly in Saccharomyces cerevisiae. Three evolved fusion variants selected from ~3500 clones presented 31- to 37-fold increases in total laccase activity, with better thermostability and broader pH profiles. The evolved α-factor prepro-leader enhanced laccase expression levels by up to 2.4-fold. Protein model analysis of these variants reveals that the beneficial mutations have influences on protein pKa shift, subunit interaction, substrate entrance, and C-terminal function.



BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9166-9179
Author(s):  
Qi An ◽  
Jie Qiao ◽  
Lu-Sen Bian ◽  
Mei-Ling Han ◽  
Xun-You Yan ◽  
...  

Different Pleurotus ostreatus and Flammulina velutipes species were compared relative to their ability to produce laccase in submerged fermentation of various lignocellulosic wastes. Fungi cultivation in identical culture conditions revealed wide differences among both species and strains of the same species. The laccase secretion ability of P. ostreatus strains was superior to F. velutipes strains. Maximum laccase production on cottonseed hull, corncob, and poplar wood was secreted by P. ostreatus CY 568, P. ostreatus CCEF 89, and P. ostreatus CY 568, respectively. The nature of lignocellulosic materials played an important role in determining the expression of laccase potential of fungi. The presence of cottonseed hull improved laccase activity and accelerated the rate of enzyme production. Maximum laccase production on cottonseed hull was nearly 1.29-fold and 1.53-fold higher than that on corncob and poplar wood, respectively. Laccase activity was detected in almost all tested strains on cottonseed hull on the first day, while only a few strains on poplar wood and corncob were detected on the first day. These findings will be helpful for selecting the appropriate strain in industrial applications and for optimization of integrated industrial laccase production.



2021 ◽  
Author(s):  
Li Meng ◽  
Xiaoran Bai ◽  
Qingji Wang ◽  
Xiaobo Li ◽  
Shaoyan Zhang ◽  
...  

Abstract Wheat bran extract may enhance laccase activity of Auricularia cornea in submerged fermentation. The laccase activity of A. cornea was maximal (768.78 U/mL) at 26.9 ℃, pH 5, a time point of 6 d, 22 h, and an inducer concentration of 10%. Laccase from A. cornea AC5 decolorized 83.27% of 75 mg/L malachite green within 12 h. High performance liquid chromatography (HPLC) analysis of the extracted metabolites suggested that the decolorization occurred through biodegradation. Malachite green induced cytotoxic damage including formation of a micronucleus and chromosome bridge at anaphase. Degradation products of malachite green proved to be less toxic and had negligible effects on chromosomal aberrations.







The application of structural analysis techniques to solve real engineering problems is an entirely independent discipline by itself that cannot be properly presented in a book of structural mechanics. However, it is important to give an overview of how mathematical models can help make engineering decisions. This is the subject of the current chapter. The context of the presentation is that of earthquake safety assessment. Of course, this is not the only industrial application of the fracture and damage mechanics of frames, but it is a very representative one and a good example of it. The chapter is organized as follows. First, the problem is presented and a protocol to solve it is described in Section 13.1. Then, an academic software that can be accessed via Internet is described in Section 13.2. This program is used to solve some examples of real structures in the last section of the chapter.



BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3017-3031
Author(s):  
Mei-Ling Han ◽  
Qi An ◽  
Kai-Yue Ma ◽  
Wen-Ning An ◽  
Wen-Yao Hao ◽  
...  

The laccase producing abilities of four Basidiomycete fungi species were compared using solid-state fermentation using four different lignocellulosic residues. The biosynthetic potential of the Basidiomycetes was highly dependent on the type of fungi. In general, the laccase secreting ability of Cerrena unicolor Han 849 was greater than Lenzites betulinus Han 851, Stropharia rugosoannulata Han 1321, and Auricularia heimuer Han 1333. The maximum laccase production of C. unicolor Han 849 was approximately 11.25, 122.26, and 15.27 times higher than L. betulinus Han 851, S. rugosoannulata Han 1321 and A. heimuer Han 1333, respectively. Different species of fungi had a preference in lignocellulosic residues. The presence of Firmiana platanifolia was conducive to secreting laccase via C. unicolor Han 849 during solid-state fermentation. A continuous and stable laccase production via C. unicolor Han 849 was an obvious advantage of solid-state fermentation with any of the four lignocellulosic residues used. The maximum laccase production of C. unicolor Han 849 using Firmiana platanifolia was approximately 2.12, 1.68, and 6.13 times higher than Populus beijingensis, Sorghum bicolor, and Oryza sativa, respectively. These findings will be helpful for developing new productivity strains in industrial applications and selecting suitable lignocellulosic residues for laccase production.



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