Bacterial Pigments As Biosynthetic Platforms: A Systematic Review Of Current Evidence

Abstract

Aim & Objectives: Bacterial pigments, a class of bioactive secondary metabolites, are gaining global interest as sustainable alternatives to synthetic dyes due to their antioxidant, antimicrobial, and UV-protective properties. This systematic review aimed to identify and classify pigment-producing bacterial species, evaluate optimisation strategies for enhancing pigment production, and assess practical industrial applications and commercial scalability of bacterial pigments.

Methods: This review was conducted in accordance with the PRISMA 2020 guidelines to ensure methodological transparency and standardized evidence synthesis. A comprehensive database search was performed to retrieve studies published in English between 2014 and 2024. Eligible studies were those that included experimental work identifying bacterial pigments and incorporated optimization techniques for pigment production. Studies focusing on nonbacterial pigment sources, review articles, and those lacking pigment identification or optimization analysis were excluded. Data extraction and quality assessment were carried out independently by multiple reviewers, ensuring that only studies with sound methodology were included in the final qualitative synthesis.

Results: Out of 1,700 initially screened articles, 63 met the inclusion criteria. A total of 84 pigment-producing bacterial species and 24 unique pigments were identified, categorized into eight pigment classes: carotenoids, phenazines, prodigiosins, violaceins, melanins, flexirubintype pigments, quinones/naphthoquinones, and polyketides. Optimization strategies included media and nutrient formulation, fermentation condition tuning, statistical design approaches, and genetic engineering.

Conclusion: Bacterial pigments are a promising avenue for sustainable pigment production with broad industrial potential. While substantial progress has been made in pigment optimization and application, further interdisciplinary research is needed to overcome barriers to large-scale manufacturing and regulatory approval.