Bio-production and characterization of carotenoid yellow pigment from Kocuria sp. GMA and exploring its sustainable antioxidant, antimicrobial and antibiofilm properties

Abstract

Bacterial pigments particularly carotenoid provide interesting prospects for a range of applications as antioxidants, antibacterial, and food additives. In-addition they are regarded as a competitive substitute for natural color production due to their better biodegradability and higher compatibility with the environment. This study aims to investigate the processes involved in producing carotenoid yellow pigment (CYP), including strain isolation and identification, pigment extraction, chemical characterization of the pigment, and testing of the pigment's antimicrobial, antioxidant, and antibiofilm properties. Using morphological traits and 16S rRNA sequencing, the isolate was recognized as Kocuria sp. GMA, with accession number OM921388. CYP from Kocuria sp .first, FTIR, LC-ESI-MS/MS spectrophotometers, and UV absorption spectra were used to chemically characterize CYP from Kocuria sp. GMA. In the pigment extract of Kocuriasp. bacteria, seven compounds, mostly carotenoids, were identified in the obtained LC-MS spectra: 224.04, 536.05, 553.22, 540.17, and 704.27, which correspond to a molecular weight of 224, 536, 552, 538.9, and 704 g/mol, which refer to Kocumarin, Lycopene, betacryptoxanthin, Neurosporene, and Flavuxanthin, respectively; peaks at m/z [M-H] lead to a molecular weight of 705.67 and 223.06, which refer to Kocumarin and Sarcinaxanthin, respectively. CYP possesses highly antioxidant activity (95.6%); this activity increased gradually with increasing concentrations and time, with an IC50 of 4.0 mg/ml at 90 min and 6.0 mg/ml at 60 min. Also, CYP showed moderate antimicrobial activity against the test pathogens with different concentrations, while it showed excellent activity as an antifungal against Aspergillus niger NRRLA-326. The MIC and MBC values of CYP against Gram-positive and Gram-negative bacteria ranged from 10 to 50 µg/ml. Results showed great antibiofilm activity of CYP against S. aureus NRRLB-767 and moderate activity against E. Coli ATCC 25922.