Screening of inducers for laccase production by Lentinula edodes in liquid medium

Abstract

Laccases are enzymes involved in lignin degradation and are produced by various organisms. Due to their low substrate specificity their potential to be used in biotechnological applications has received attention. The addition of laccase inducers to the culture medium of microorganisms can enhance laccase production and facilitate its purification and utilization. The aim of this study was to investigate the effect of some compounds as laccase inducers in cultures of Lentinula edodes (shiitake). First, it was selected a culture medium suitable for laccase production by shiitake using two levels of N (2.6 and 26 mM) and seven levels of Cu (0, 50, 100, 150, 200, 250 and 300 µM). The medium with 2.6 mM N and 250 µM Cu was found to provide the highest laccase activity. To the selected medium it were added gallic acid (1 mM), catechol (1 mM), ammonium tartrate (55 µM), hydroxybenzoic acid (1 mM) and vanillin (1 mM). The two first compounds completely inhibited laccase activity and a 30 day time course experiment was carried out with the remaining compounds. Only cultures with ammonium tartrate exhibited laccase activity higher than control cultures, reaching 251 U/ mL of extract after 30 days. A native-PAGE was performed and showed only one band, suggesting that no isozyme was produced.

Production and characterization of tyrosinase activity in Pycnoporus sanguineus CCT-4518 crude extract

“…Ten 5 mm diameter mycelium discs were inoculated in 50 mL of malt extract broth (Merck, Darmastadt, Germany) plus substrate (4, 19, 28). Cultures were grown in conical flasks (250 ml) with shaking (150 rpm) at 30°C for 7 days (16).…”

Effect of inducers on the decolorization and biodegradation of textile azo dye Navy blue 2GL by Bacillus sp. VUS

“…The addition of inducers to the culture medium showed faster decolorization might be due to an enhancement of LiP and laccase production that facilitate its utilization (Rodriyguez Couto et al 2002;Cavallazzil et al 2005). An induction in the activity of LiP and laccase, and the reduction in the time of decolorization indicate the vital role of some chemical compounds which serves as inducers of the enzymes.…”

Production of laccase by Pynoporus sanguineus using 2,5 - Xylidine and ethanol

“…However, high amounts of the enzyme are needed for these applications, as well as to other studies. In this way, researches have been developed in order to increase laccase production by the use of new sources (9, 18) and by screening for inducers of laccase production by microorganisms, like aminoacids (3), aromatic compounds (2), copper (17) and agro-residues (21). The presence of laccases has been reported in many fungal species, but relatively few researches have been directed towards the laccase produced by members of the genus Pycnoporus .…”