Optimization of Carotenoid Production from Microbacterium oleivorans SAA1517and its Application as Fish Feed

Author: Samruddhi J. Patil and Anuradha S. Pendse

Download PDF

Abstract

Carotenoids are structurally and functionally diverse groups of pigments produced by plants, animals and microorganisms. These compounds have received considerable attention due to their sustainable nature and potential health benefits. The present study was carried out to screen carotenoid producing bacteria from diverse soil samples and optimize their yield. The most challenging aspect of the study was distinguishing between carotenoid-producing bacteria and non-carotenoid pigment-producing bacteria. In addition, the extraction of carotenoids posed some difficulty as it necessitated the use of organic solvents. The samples were collected from farm fields, mangrove and garden rhizosphere regions. Among the 18 isolates, Microbacterium oleivorans SAA1517, was identified as the most potential carotenoid producer based on spectrophotometric (showing λmax at 465nm), qualitative (ring test) and TLC (Rf value of 0.65) analysis. The gene sequence of this isolate was submitted to the gene bank (accession no LC224329). The novel strain produced a dark orange pigment and showed maximum yield in Luria Bertani medium containing galactose and sodium nitrate in 3:1 ratio. The pigment production was optimum at pH 7, temperature 30°C, shaker conditions (120rpm) and presence of 2% inoculum size (0.9 O.D545nm). Methanol was the most effective solvent for extraction of pigment. The antioxidant, antibacterial activity of the pigment, and its efficacy as feed supplement using goldfish were also evaluated. It showed good anti-oxidation potential with IC50 4.2μg/mL and significant antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes, Proteus mirabilis and Pseudomonas aeruginosa. Determination of survival rate, weight gain, specific growth rate and feed conversion rate further confirmed that carotenoid supplements significantly improved the growth rate of goldfish. In the future, enhancing the fermentation conditions can significantly enhance the production of carotenoid pigments, which hold great promise as a natural and sustainable ingredient for fish feed in aquaculture. Additionally, incorporating bacterial carotenoids into fish feed has the potential to reduce the reliance on synthetic pigments and mitigate the environmental impact of aquaculture.

Keywords

Carotenoids, Microbacterium oleivorans, optimum, pigment, screening

Conclusion

Considering the great demand of pigments in various industries, the use of microbial sources for its production is a practical as well as sustainable strategy to meet the market demands. Though the microbial production studies are in preliminary stages at present, it is a potential biotechnological tool. In this aspect, genetic engineering to strain improvement, genome engineering and fermentation strategies to scale-up production to industry level etc. play vital roles in maximizing the yield of microbial secondary metabolites. The carotenoid production ability of M. oleivorans SAA1517 was improved by 53.125% under optimized conditions in the present study. Comprehending the fact that the optimization studies carried out in 250ml shaker flasks under laboratory conditions enhanced the carotenoid production significantly in a non-photosynthetic bacterium, it is a potential candidate for scale up studies using larger fermenters.

References

-

How to cite this article

Samruddhi J. Patil and Anuradha S. Pendse (2023). Optimization of Carotenoid Production from Microbacterium oleivorans SAA1517and its Application as Fish Feed. Biological Forum – An International Journal, 15(2): 323-332.