A novel promising laccase from the psychrotolerant and halotolerant Antarctic marine Halomonas sp. M68 strain

Abstract

Microbial communities inhabiting the Antarctic Ocean show psychrophilic and halophilic adaptations conferring interesting properties to the enzymes they produce, which could be exploited in biotechnology and bioremediation processes. Use of cold- and salt-tolerant enzymes allows to limit costs, reduce contaminations, and minimize pretreatment steps. Here, we report on the screening of 186 morphologically diverse microorganisms isolated from marine biofilms and water samples collected in Terra Nova Bay (Ross Sea, Antarctica) for the identification of new laccase activities. After primary screening, 13.4 and 10.8% of the isolates were identified for the ability to oxidize 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and the dye azure B, respectively. Amongst them, the marine Halomonas sp. strain M68 showed the highest activity. Production of its laccase-like activity increased six-fold when copper was added to culture medium. Enzymatic activity-guided separation coupled with mass spectrometry identified this intracellular laccase-like protein (named Ant laccase) as belonging to the copper resistance system multicopper oxidase family. Ant laccase oxidized ABTS and 2,6-dimethoxy phenol, working better at acidic pHs The enzyme showed a good thermostability, with optimal temperature in the 40–50°C range and maintaining more than 40% of its maximal activity even at 10°C. Furthermore, Ant laccase was salt- and organic solvent-tolerant, paving the way for its use in harsh conditions. To our knowledge, this is the first report concerning the characterization of a thermo- and halo-tolerant laccase isolated from a marine Antarctic bacterium.

Lignin Valorization: Production of High Value-Added Compounds by Engineered Microorganisms

“…Recently, from the marine Halomonas sp. strain M68 isolated from marine biofilm and water samples collected in Terra Nova Bay (Antarctica), an intracellular thermoand halo-tolerant laccase-like activity, with an optimal temperature in the 40-50 • C range, was isolated [47].…”

Laccase-Treated Polystyrene Surfaces with Caffeic Acid, Dopamine, and L-3,4-Dihydroxyphenylalanine Substrates Facilitate the Proliferation of Melanocytes and Embryonal Carcinoma Cells NTERA-2

“…The versatility of laccase has, among other things, recently been reported in the degrading of antibiotics with Bacillus sp. FNT , enhancing lignocellulose breakdown, synthesizing polymers for food packaging, and decolorizing dyes using a hybrid nanobiocatalyst [ 19 , 22 , 23 , 24 , 25 , 26 ]. However, few studies have focused on laccase application on the interface treatments for improving surface chemistry, especially for cell cultivation.…”

Optimization of laccase from Stenotrophomonas maltophilia E1 by submerge fermentation using coconut husk with its detoxification and biodecolorization ability of synthetic dyes

“…Furthermore, recent research efforts have resulted in the discovery of novel laccase variants with unique properties. These enzymes exhibit increased stability, substrate specificity and tolerance to harsh conditions, making them promising candidates for various biotechnological applications (Bisaccia et al 2023 ; Chauhan et al 2017 ). Automation and high-throughput screening techniques have accelerated the process of identifying laccase-producing bacteria.…”