Optimization of Bacillus licheniformis MAL tyrosinase: in vitro anticancer activity for brown and black eumelanin

Abstract

The influence of tyrosinase in catalyzes/stimulates the eumelanin production was studied. Accordingly, bacterial sp. was isolated and identified as Bacillus licheniformis based on 16S rRNA . It could grow and gave monophenolase and diphenolase productivity in medium contained tyrosin and Cu 2+ only. The tyrosinase enzymes were optimized by studying different environmental and nutritional factors. The maximum monophenolase and diphenolase productivity were obtained at 60 °C, pH9, Cu 2+ (0.01g), liver extract (1 g/L) and the oxygen level fixed at 20%. Also, the mannose as a carbon source increased the monophenolase production 6.2 times. For the first time, two types of eumelanin were extracted by hydrochloric acid treatment. The black and brown eumelanin weighed (0.1 g/100 mL and 0.7 g/100 mL respectively) and characterized by using FTIR and UV/Vis spectroscopy techniques. Their morphological structure and its elemental composition were characterized by SEM and EDAX respectively. The black melanin showed promising anticancer activity towards HEPG-2 and HCT-116 cell lines with IC 50 values (6.15, 5.54 μg) compared to Doxorubicin (4.05, 4.45 μg) respectively.

Suggested Sustainable Medical and Environmental Uses of Melanin Pigment From Halotolerant Black Yeast Hortaea werneckii AS1

“…In terms of the effect of H. werneckii AS1 melanin pigment on cancerous cell lines, a mild effect was detected at a concentration of 100 μg/ml on the malignant HepG2 cell line, with a reduction percentage of roughly 39%. These findings seem to be in contrast with the results gained by Shalaby et al (2019) who stated that using SRB cytotoxicity assay, Bacillus licheniformis MAL black eumelanin exhibited an encouraging anticancer action against human hepatocellular carcinoma (HepG2) and colon carcinoma (HCT-116) cell lines with an IC 50 rate of 6.15 and 5.54 μg, respectively, in comparison with Doxorubicin, which had IC 50 values of 4.05 and 4.45 μg ( Shalaby et al, 2019 ). Furthermore, Kurian et al (2015) documented that marine Bacillus spp.…”

Melanin biosynthesis in bacteria, regulation and production perspectives

“…The first crystal structure resolved of a tyrosinase was that of the Streptomyces castaneoglobisporus, revealing that the enzyme dinuclear Cu center is flexible and that this flexibility is important for its catalytic specificity (Matoba et al 2006). Tyrosinases involved in the synthesis of melanin are present in Gram-positive and Gram-negative bacteria, such as Sinorhizobium meliloti (Mercado-Blanco et al 1993), Ralstonia solanacearum (Hernández-Romero et al 2005), Marinomonas mediterranea (López-Serrano et al 2004;Solano et al 2000), Pseudomonas putida (McMahon et al 2007), Vibrio tyrosinaticus (Pomerantz and Murthy 1974), Vibrio nigripulchritudo (Goudenège et al 2013), Saccharophagus degradans (Kelley et al 1990;Ekborg et al 2005), Bacillus thuringiensis (Liu et al 2004), Bacillus megaterium (Shuster and Fishman 2009), and Bacillus licheniformis (Gamal Shalaby et al 2019). Bacterial tyrosinases were reviewed by Claus and Decker (2006), Sanchez-Amat et al (2010), Faccio et al (2012), andFairhead and.…”

Characterization of an Insoluble and Soluble Form of Melanin Produced by Streptomyces cavourensis SV 21, a Sea Cucumber Associated Bacterium

“…While PDM showed a rather uniform amorph fers a conglomerate of different irregular structures that are likely deriv plex branching and filamentous arrangement as seen in Figure 1D. morphological structure to insoluble eumelanin isolated from Bacillus [31]. Besides C, N, and O, PDM also contained Mg, S, P, Ca, Fe, and Cu (Figure 2D).…”

“…While PDM showed a rather uniform amorphous shape, PM offers a conglomerate of different irregular structures that are likely derived from their complex branching and filamentous arrangement as seen in Figure 1D. PDM has a similar morphological structure to insoluble eumelanin isolated from Bacillus licheniformis MAL [31].…”