Production of melanin by soil microbial isolate on fruit waste extract: two step optimization of key parameters

Abstract

In this study, optimization of production parameters influencing melanin production in an economical fruit waste extract was attempted using a garden soil isolate (Bacillus safensis). Taguchi approach was adopted for screening of critical parameters and further optimization was done using a central composite design of response surface methodology (RSM). At optimum conditions (pH 6.84 and Temp 30.7 °C), a significant yield of ∼6.96 mg/mL was observed. Statistical analysis revealed that the experimental results fitted well to the statistical model with model R2 value 0.982. The optimization of process parameters using RSM reported a 15% increase in the pigment yield than average yield obtained from the studied model. The melanin produced was confirmed by UV–visible spectroscopy, FTIR and XRD analysis. Moreover melanin obtained has significant photoprotective, radical scavenging and metal chelating activity. Thus, B. safensis has the potential to be a new source for the production of melanin, which is of industrial interest.

Copper and Melanin Play a Role in Myxococcus xanthus Predation on Sinorhizobium meliloti

“…As shown in Figures 4A,B, the FT-IR spectra obtained of the solid brown pigment extracted in both samples were very similar. Moreover, these spectra exhibited several features that are identical to those described for bacterial melanins of E. coli (Chávez-Béjar et al, 2013;Mejia-Caballero et al, 2016), Lysobacter oligotrophicus (Kimura et al, 2014), Azotobacter chroococcum (Banerjee et al, 2014), Pseudomonas (Tarangini and Mishra, 2013), Streptomyces cyaneofuscatus (Al Khatib et al, 2018), Bacillus weihenstephanensis (Drewnowska et al, 2015), and soil bacteria (Tarangini and Mishra, 2014). Nevertheless, to further confirm that the pigment was melanin, the absorbance in UV-V of pigments extracted in NaOH from a pure culture of S. meliloti GR4 and a co-culture with M. xanthus following a modified version of the protocol described by Whittaker (1963) (see section "Materials and Methods" for details) was also determined.…”

Agro-Industrial Waste Revalorization: The Growing Biorefinery

“…Different microorganisms such as Streptomyces, Serratia, Cordyceps, Monascus, and Paecilomyces, Penicillium atrovenetum, Penicillium herquei, Rhodotorula, Sarcina, Cryptococcus, Phaffia rhodozyma, Pseudomonas, Bacillus sp., Vibrio, Monascus purpureus, Achromobacter, Ya r r o w i a , and Phaffia have shown their potential in pigment production as a major source of blue and yellow-red pigments [39]. Other important pigment is the melanin, which is present in animals, plants, and microorganisms to provide stress protection against UV radiation, oxidation, and defense [40]. This pigment is used for the cosmetic and pharmaceutic industries with a photoprotective and antioxidant importance in different products.…”

Physiologically Active Compounds in the Products of Microbiological Decomposition of Straw of Cereals, and Their Effect on Growth and Yield of Plants in Unfavorable Conditions

“…Вероятно, что усиление ростовых процессов и увеличение урожайности пшеницы при аномально повышенных и пониженных температурах, характерных для лета 2014 г., связано с наличием в экотоле меланинов [Goncalves, Pombeiro-Sponchiado, 2005; Тоноян и др., 2010; Азарян, Мелконян, 2014; Гесслер, Егорова, Белозерская, 2014; Kurchenko et al, 2006;Tarangini, Mishra, 2014]. Повышению устойчивости растений и активации их роста могло также способствовать присутствие в экотоле ауксина, который, как известно, положительно влияет на эти процессы, что было показано в экспериментах с продуцирующими ауксины микроорганизмами (Kudoyarova et al, 2017) Ауксины выполняют большое количество разнообразных физиологических функций, активно участвуют в ростовых процессах растений [Медведев, 2004, с.…”