Smitha, K.V., Sooraj S. Nath, and Kunhi, A.A.M. 2015. Isolation of a yellow pigment producing bacterium from soil and partial characterization of the pigment. National Conference “Role of biopharmaceuticals in achieving health by 2020” (NCRBH2k5), 10-11thJuly 2015, Dr. N.G.P. Arts and Science College, Coinbatore-641 048, Tamil Nadu, India. Abstract Book, p. 95.


                        Some bacteria produce pigments for various reasons and they play important roles. The rapid emergence of drug resistance among pathogenic bacteria, especially multi drug resistant bacteria, underlines the need to look for new antibacterial compounds. Synthetic colouring agents have been shown to be potential carcinogens. Natural colours extracted from fruits, vegetables, seed roots, and microorganisms commonly called ‘bio-colours’, due to their biological origin, have proved to be safe colouring agents. A yellow pigment producing organism was isolated from soil collected from Vazhayoor East, Kerala. By morphological and biochemical tests, this isolate has been tentatively identified as Micrococcus varians. The pigment was extracted by using acetone and ethanol. Spectral analysis of the pigment was carried out using a spectrophotometer and a peak was obtained at 439 nm. From this and other analyses the pigment was tentatively identified as a carotenoid, probably Neoxanthin. Optimization of cultural and  physico-chemical conditions indicated that the maximal production of the carotenoid (Neoxanthin) was at 30C and pH 7. Peanut meal in nutrient broth, among various substrates tested,  showed maximum pigment production. Antibacterial sensitivity test conducted on multiple drug resistant strains of Staphylococcus aureus and Pseudomonas sp. clearly indicated a strong antibacterial activity of the pigment produced by Micrococcus varians. The antimicrobial compounds produced by this strain will be useful in developing antibiotics against drug resistant bacteria.