First report of betalain production from endolichenic Bacillus sp. LDAB???1 from Dirinaria aegilita: Insights from novel quantification methodology of image processing

Context & Rationale

The widespread use of synthetic food colorants has raised considerable concern owing to their documented genotoxic, carcinogenic, and hypersensitivity-inducing properties. This has prompted sustained scientific interest in identifying natural, microbially derived pigment sources that offer both safety and functional benefits. Among pigment classes of current interest, betalains ??? water-soluble, nitrogen-containing compounds with established antioxidant and nutraceutical properties ??? present a compelling candidature, yet their production from bacterial sources, particularly those of lichenous origin, remains largely uninvestigated.

Scope of the Study

This study investigates the pigment-producing potential of endolichenic bacteria associated with Dirinaria aegilita, a lichen known to harbour diverse and metabolically active bacterial consortia. A red pigment-producing isolate, designated Bacillus sp. LDAB-1, was subjected to rigorous morphological, biochemical, protein-based, and molecular characterisation. The identity and functional properties of the pigment produced were evaluated through a suite of spectroscopic and chromatographic techniques, the findings of which constitute the first report of their kind in the scientific literature.

Key Findings

The pigment produced by Bacillus sp. LDAB-1 was confirmed to belong to the betalain class, exhibiting physicochemical and spectral characteristics consistent with this group. Antioxidant evaluation via the DPPH radical scavenging assay yielded results of considerable significance ??? findings that invite direct comparison with widely employed reference standards and warrant careful examination of the data presented in the full manuscript.

Methodological Innovation

In addition to the biological discovery, this study advances a novel image processing-based methodology for pigment quantification, employing smartphone imaging and computational colour space analysis as a viable alternative to conventional spectrophotometric techniques. The method was formally validated against fluorescence spectroscopy, and the outcomes of this comparative assessment ??? including the identification of the most discriminating colour space parameter ??? are reported and discussed in detail within the publication.

Keywords

Bacillus sp. ?? Betalains ?? Dirinaria aegilita ?? Endolichenic bacteria ?? Image processing ?? Natural pigments ?? Antioxidant activity ?? L*a*b* color space ?? Nutraceuticals ?? MALDI-TOF MS