The objective of this investigation was to explore the antioxidant and antimicrobial property of bioactive prodigiosin produced from using rice bran. The antioxidant potential of prodigiosin was examined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging method via UV-visible, electron spin resonance spectrum (ESR), cyclic voltammetry and excitation emission spectrum. The antimicrobial activity of prodigiosin was examined against foodborne pathogens. The shelf life extending capacity of prodigiosin was evaluated with meat extract powder (MEP) as a model food material. The DPPH and ABTS radicals were completely scavenged by prodigiosin at the concentration of 10 mg/L. The food spoilage was inhibited by the addition of prodigiosin with MEP and it was compared with conventional preservative. The prodigiosin has prohibited the growth of foodborne pathogens effectively and the shelf life of the food was also extended significantly. The antimicrobial edible preservative developed in this study inhibited the growth of the microbial populations that produced through storage of the MEP and free radical scavenging activity. The results reveal that the bioactive prodigiosin effectively scavenged the free radical and inhibited the bacterial growth in food stuff.

The prodigiosin impregnated column reactor (PICCR) was developed for the removal of pathogenic bacteria from water/wastewater. The impregnation of prodigiosin on cellulose matrix significantly improved the activity and stability.

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Cheap and efficient bioactive materials capable of producing potable water are in high demand. We synthesized bioactive prodigiosin-conjugated iron-oxide-activated carbon composite ([Ac] F @Fe 3 O 4 −PG) for the effective removal of microbial contaminants without biofilm formation. The disinfection effect of [Ac] F @Fe 3 O 4 −PG was investigated against antibiotic-resistant Escherichia coli and Bacillus cereus. The reactive oxygen species, glutathione concentration, and intracellular leakages assay, zeta potential, atomic force microscopy, scanning electron microscopy, and fluorescence microscopy were performed to understand the mechanistic route of bacterial disinfection. Results demonstrate the bacterial cell membrane damage due to the surface charge neutralization by cationic [Ac] F @Fe 3 O 4 −PG, thereby affecting the transport system of the cells. The generation of reactive oxygen species further triggered programmed bacterial cell death with apoptosis-like changes in cellular morphology. We demonstrate that the [Ac] F @Fe 3 O 4 −PG matrix is reusable and has long-term antibacterial activity with efficient inhibition of biofilm formation. The study reveals that the [Ac] F @Fe 3 O 4 −PG could be a promising disinfectant for both Gram-negative and Gram-positive pathogens for effective environmental applications.

Anaerobic digestion of post-tanning wastewater was performed in batch anaerobic digester to evaluate the effect of COD/sulphate ratio [0.62, 0.69, and 1.20 (w/w) %] and F/M ratio [0.2, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, and 1.5 (w/w) %)] on the removal efficiency of COD. The F/M ratio of 0.3 was found to be the optimum ratio for the removal of COD by 53, 57, and 65%, respectively at COD/sulphate ratio of 0.62, 0.69, and 1.20. The maximum sulphate removal was observed at F/M ratio of 0.2 and the removal efficiency was 48, 50, and 58% at COD/sulphate ratio of 0.62, 0.69, and 1.20, respectively. The removal efficiency of COD and sulphate was increased with increase in COD/sulphate ratio from 0.62 to 1.20 and decreased with increase in F/M ratio from 0.2 to 1.5 in anaerobic digestion of post-tanning wastewater. The maximum concentration of sulphide formation was 784 mg/L at COD/sulphate ratio of 0.62 in anaerobic digestion process and the process was inhibited at this sulphide concentration. The microbial activity in the sludge was evaluated through live and dead cell assay using fluorescent microscopy. The maximum amount of dead microbes was observed in the anaerobic digester, which was operated at COD/sulphate ratio of 0.62 than other studied ratio.