Isolation, Characterization, and Optimization Studies of Bacterial Pigments

Abstract

Recent concern for human safety and environmental protection has rekindled interest in natural pigment sources. In comparison to synthetic pigments, microbial pigments show better biodegradability and environmental compatibility and are used in a variety of applications ranging from food to cosmetics. The areas of attention for economical pigment synthesis include the identification of novel microbiological sources and improvement of process parameters. The purpose of this research was to screen and identify microbial isolates capable of generating pigments with antimicrobial activity from a variety of soil samples. A total of six pigment-producing bacterial sps were able to isolate from various soil samples such as bore well digging sites, river shores, river beds, forest areas, dumping yards using the enrichment culture technique. All the isolates were morphologically and biochemically identified as Micrococcus sp producing two-color pigments i.e., yellow and orange, Serratia sp producing red and pink color pigments, Salinococcus sp producing orange color pigment, and Exiguobacterium sp producing yellow color pigment respectively. During optimization studies maximum pigment production was observed at pH 7, agitation at 90 rpm (rotations per minute) and 120 rpm, the temperature of 30°C and 37°C, inoculum size up to 2% with NaCl concentration of 2%, 4%, and 6% respectively. Optimization of nutritional parameters such as carbon source and nitrogen source it was found that glucose (1%) and yeast extract (0.1%) work the best. Extraction of the pigment from the fermented broth was done by solvent-solvent extraction method. UV-Visible spectrophotometry and Silica gel Thin-layer chromatography was used to detect the presence of carotene and prodigiosin in the extracted bacterial pigment. The crude bacterial pigments were tested for antimicrobial activity against clinical pathogens including E. coli, Klebsiella sp, Bacillus sp, Staphylococcus sp, and pseudomonas sp respectively. Among all the isolates, pigments of Micrococcus sp and Salinococcus sp showed comparatively good results. Further purification of the pigment will lead to discovering a promising drug in the pharmaceutical industry.

Optimized carotenoid production and antioxidant capacity of Gordonia hongkongensis

“…indicated a favorable effect of inoculum concentration on pigment generation, peaking at 2 g/L. 43 This aligns with our optimization findings, reinforcing the notion that this specific inoculum concentration supports rapid mycelial growth, ultimately enhancing pigment and antioxidant metabolite production. 45 In the case of G. alkanivorans strain 1B, Fernandes et al (2018) found that the stress experienced by the strain was pivotal for carotenoid production, particularly under prolonged exposure to light at varying lux levels (400-3000 lux after 19 days).…”

“…These variables directly impact the maximization or limitation of desired metabolites, emphasizing the importance of identifying and optimizing the right combination of culture conditions. 43 As a result, the fermentation process of actinomycetes for pigment and antioxidant production is intricate. It greatly depends on yield, culture medium, and inoculum and necessitates specific environmental conditions pH, temperature, and stirring speed.…”

“…Conversely, the lowest value (0.04) was observed in run No. 43, with an inoculum concentration of 0.5 g/L, starch concentration of 2 g/L, malt extract concentration of 10 g/L, yeast extract concentration of 4 g/L, NaCl concentration of 30 g/L, pH at 6.5, a 7-day incubation period, a temperature of 30°C, and an agitation speed of 180 rpm. Analyzing the main effects of each variable (Figure S5), six factors, i.e.…”

Study on Exiguobacterium Acetylicum Ki3 Strain Pigment Optimization Andantibacterial Activity

“…Physical parameters of bacterial pigment production : The pigmented colony underwent incubation at temperatures (25-40°C) and pH (4-14) for 24 hours, yielding maximum pigment production, assessed via OD at 425nm. UV exposure (30sec-5min) followed by 37°C incubation for 24 hours induced mutations, enhancing pigment production, measured similarly (Fatima et al, 2022) (Fatima Shatila et al, 2013).…”

Untitled

“…It is very important to investigate the potential of microbial pigment, to use it in various industries. The antimicrobial activity of the pigment is tested by antibacterial and antifungal assay 5 . Both gram positive and gram-negative bacteria are susceptible to antimicrobial effects of bacterial pigment 6 .…”