Bacteria as a source of biopigments and their potential applications

From the prehistoric period, the utilization of pigments as colouring agents was an integral part of human life. Early people may have utilized paint for aesthetic motives, according to archaeologists. The pigments are either naturally derived or synthesized in the laboratory. Different studies reported that certain synthetic colouring compounds were toxic and had adverse health and environmental effects. Therefore, knowing the drawbacks of these synthetic colouring agents now scientists are attracted towards the harmless natural pigments. The main sources of natural pigments are plants, animals or microorganisms. Out of these natural pigments, microorganisms are the most important source for the production and application of bioactive secondary metabolites. Among all kinds of microorganisms, bacteria have specific benefits due to their short life cycle, low sensitivity to seasonal and climatic variations, ease of scaling, and ability to create pigments of various colours. Based on these physical characteristics, bacterial pigments appear to be a promising sector for novel biotechnological applications, ranging from functional food production to the development of new pharmaceuticals and biomedical therapies. This review summarizes the need for bacterial pigments, biosynthetic pathways of carotenoids and different applications of bacterial pigments.

Characterization of β-Cryptoxanthin and Other Carotenoid Derivatives from Rhodotorula taiwanensis, A Novel Yeast Isolated from Traditional Starter Culture of Assam

The present investigation was intended to characterize pigments for the first time from Rhodotorula taiwanensis (LC011412) yeast isolated from the ethic fermentation starter culture source meant to evaluate its carotenoid contents for beneficial applications. The pigments were extracted by an optimized solvent system, purified by flash chromatography and were identified by TLC and UV/VIS spectroscopy. The absorbance spectra confirmed the presence of β-carotene, β-cryptoxanthin, torulene and torularhodin that showed maximum absorbance (λ_max ) within the ranges. The fractions were further characterized by LC/MS and analyzed through FT-IR and NMR for structure elucidation. Spectral analyses also confirmed the presence of the compounds mentioned above. These compounds promise great commercial value and could be useful for large scale production anticipated for potential applications in food, nutraceutical, pharmaceutical and cosmetic sectors. It is pertinent that the characterized carotenoid pigments from the isolate have incredible prospects in industrial applications which require profound attention.

Signals for a transition from surface to bulk emission in thermal multifragmentation

Excitation-energy-gated two-fragment correlation functions have been studied between E(*)/A = (2-9)A MeV for equilibriumlike sources formed in 8-10 GeV/c pi(-) and p+197Au reactions. Comparison with an N-body Coulomb-trajectory code shows an order of magnitude decrease in the fragment emission time in the interval E(*)/A = (2-5)A MeV, followed by a nearly constant breakup time at higher excitation energy. The decrease in emission time is strongly correlated with the onset of multifragmentation and thermally induced radial expansion, consistent with a transition from surface-dominated to bulk emission expected for spinodal decomposition.