Independent behavior of bacterial laccases to inducers and metal ions during production and activity

Abstract

Laccase, a blue copper oxidase, is an enzyme that is involved in the oxidation of aromatic compounds which prove otherwise difficult to degrade in the environment. The substrates of laccase are xenobiotics and synthetic dyes. The isolation of bacterial strains was investigated for laccase production and its activity. The medium for production was a high nitrogen medium containing aromatic compounds as inducers, for instance, guaiacol, phenol red and black liquor (from pulp and paper industry) gave higher production. The enzymes of isolated bacteria had the optimum pH and temperature in the range of 3 to 5 and 32 to 37°C, respectively. Furthermore, metal ions had an effect on the laccase enzyme; MnSO 4 and CuSO 4 showed a significant increase in laccase activity. However, the effects of metal ions on either laccase production or laccase activity were not clear. The laccase production and activity were dependent on species of bacterial strains. The laccase bacteria were identified as Rhodococcus sp., Enterobacter sp., Staphylococcus saprophyticus and Delftia tsuruhatensis. The synthetic dyes were determined in the reduction of color using the G32 strain; this strain gave 20 to 65% of dye reduction within three days.

Bioprospecting and molecular characterization of laccase producing bacteria from paper mills of Himachal Pradesh

“…Similarly, laccase producing bacteria c-proteobacterium JB was isolated from industrial waste water drained soil samples [16] and laccase producing bacteria was also cultivated from wastewater of a pulp and paper industry [17]. Mongkolthanaruk et al also obtained laccase producing bacteria from soil and wastewater of the pulp and paper industry [13]. However, first report on laccase activity has been from the rhizosphere of rice i.e.…”

“…Guaiacol is used as it is a substrate, which is chromogen in nature leading to successful screening of laccase producers, which were able to produce extracellular guaiacol oxidising enzymes, and it can also act as best source of carbon for laccase production whereas copper ions were also added to the medium during enrichment culture. It is well known that copper ions are toxic even at low concentrations to lots of [13]. A total of 74 bacterial isolates were obtained from 18 paper mill samples.…”

“…Selected laccase producing bacterial strains were further screened for laccase activity using modified method of Mongkolthanaruk et al [13]. The culture supernatant was obtained by centrifugation of overnight cultures of selected bacterial isolates at 10,000 rpm at 4°C for 10 min and used as crude extracellular enzyme.…”

Pilot scale production of extracellular thermo‐alkali stable laccase from Pseudomonas sp. S2 using agro waste and its application in organophosphorous pesticides degradation

“…On the basis of the available literature, enhancement of laccase activity was shown in the presence of Cu +2 , Co +2 , Li + and Ca +2 with Bacillus tequilensis SN4 and Staphylococcus saprophyticus, Delftia tsuruhatensis, Enterobacter sp., and Rhodococcus sp., and laccase activity was inhibited by Mn +2 , Fe +3 and Ni +2 in the case of Bacillus tequilensis SN4 . It is hypothesized that metal ions (Fe +3 ) react with the electron transport chain of the enzyme and thereby inhibit enzyme activity .…”

Selection and optimization of lignocellulosic substrate for laccase production from Pleurotus species

“…Selim et al (2013) reported similar results by showing that laccase production reached the maximum value with supplementation of Ca 2+ (0.730 U/ml) and decreased with Fe +2 (0.49 U/ml). Mongkolthanaruk et al (2012) also indicated that Ca 2+ activated more laccase production. The requirement for specific metal ions depends on the organisms, that is different organism prefers different metal ions and thus the product varies.…”