Efficient production of Al(OH)₃-immobilized laccase with aHeterobasidion annosumstrain selected by microplate screening

Abstract

Aims: Wild‐type white rot fungi are the most important production organisms for laccase, a promising oxidative biocatalyst with numerous applications. This study aimed at identifying novel highly productive strains, finding optimal cultivation conditions for laccase production and establishing a simple immobilization procedure. Methods and Results: By using a newly developed 96‐well microplate cultivation method, 23 species of white rot fungi, represented by 29 strains, were directly compared with regard to the amount of secreted laccase. Both, with glucose and spruce saw dust as growth substrate a Heterobasidion annosum strain and a Physisporinus vitreus strain were the most productive (730–2200 U l−1 of secreted laccase). Cultivation conditions for laccase production with H. annosum were optimized in larger‐scale liquid cultures. Aeration with a sparger lead to a 3·8‐fold increase in laccase activity when compared to nonaerated flask cultures. More than 3000 U l−1 laccase was produced in glucose medium supplemented with yeast extract and the inducer veratryl alcohol. Culture supernatant was incubated with short‐range ordered Al(OH)3 particles to directly immobilize and concentrate laccase by adsorption. Active laccase was recovered in 40% yield and the Al(OH)3‐adsorbed laccase was suitable for repeated decolourization of indigo carmine. Conclusions: Microplate cultivation allowed a large‐scale comparison of the capacity of different fungal species for laccase production. Laccase secretion of a highly productive H. annosum strain was found to vary strongly with different cultivation conditions. Adsorption to Al(OH)3 proved to be suitable as direct immobilization technique. Significance and Impact of the Study: The microplate screening method simplifies strain and medium development for laccase production. Two novel fungal strains suitable for laccase production were identified. Procedures for simple and efficient production of immobilized H. annosum laccase were established.

Enzyme Activities of Five White-Rot Fungi in the Presence of Nanocellulose

“…Laccase production was higher than observed with the same T. versicolor 159 Empa strain in standing cultures grown with glucose and veratryl alcohol (122 ± 24 U/L) or spruce wood sawdust (198 ± 44 U/L) ( Table 2). Additionally, the laccase activities of R. vitreus 643 in standing cultures (603 ± 75 U/L) were similar to those observed when the same culture was grown with spruce wood sawdust (755 ± 148 U/L) [53]. These results show that TEMPO-oxidized CNF and CNC stimulates laccase production in T. versicolor 159 and R. vitreus 643 similar to more complex lignocellulosic substrates.…”

A new technique to estimate percentage decolorization of synthetic dyes on solid media by extracellular laccase from white-rot fungus

“…In previous study, the presence of laccase was detected in Resinicium bicolor that confirmed the micro plate laccase screening (Ihssen et al 2011). Furthermore, the different physical and chemical factors important for the production of laccase was also screened (Shah, Yusof, and Alam 2014).…”

Protection of Wood from Microorganisms by Laccase-Catalyzed Iodination

“…They showed that C. puteana was more susceptible to the inhibitory action of the tested compounds than T. versicolor because it produced less extracellular laccase (which catalyzed the oxidation of the phenolic compounds, thereby reducing their antifungal activity). Even though we could not detect a higher susceptibility of the brown rot O. placenta in comparison to T. versicolor, the results reported by Voda et al (60) and from the present study suggest that an important function of laccases might be detoxification of bioactive compounds produced by plants (8,32,57), in addition to their wellknown involvement in lignin modification (57).…”