Abstract
Dyes are chemicals found in industrial water discharge, which may harm aquatic life and humans. In this study, halophilic bacteria was isolated from sea water in Jeddah, KSA, and then identified using 16SrDNA sequencing technique. Mathematical modeling has been achieved to predict the number of runs needed to reach the maximum of dye removal. Then the effect of four independent variables (NaCl concentration, Peptone concentration, temperature and agitation) was studied using full Factorial Design (FFD) for the determination of optimal abiotic and biotic condition, which reaches a maximum percentage of colour removal (% of decolourization) in artificial seawater (ASW). A model was proposed for the statistical analysis of colour removal prediction. Analytical techniques (UV–vis and FTIR) was also used to determining the degradation mechanisms. The active strain was then genetically characterized to identify genes related to chemical and dyes biodegradation.
The isolated strain was identified as Photobacterium ganghwense. Our results revealed that P. ganghwense (5.106 CFU/ mL) was able to decolourize four tested dyes (Methyl orange, Congo red, Crystal violet and Malachite green) in modified ASW with different degrees and the maximum of decolourization was attributed to malachite green (79.61%). The biodegradation capability of the selected strain was confirmed by UV–Vis spectrum and FTIR analysis. Experimental data and model predictions were found to be in good agreement. Genomic analysis confirm the presence of several enzymes (reductase, dehydrogenase, oxidase, kinase, hydrolase, and transferase) associated with dyes and xenobiotic degradation, indicating its possible use in biotechnology applications.
•Mathematical modelling and statistical analysis have been achieved to predict the number of runs needed to reach the maximum of dye removal.•Full Factorial Design was applied to determine the effect of NaCl, peptone concentration, temperature and agitation on dyes removal in ASW.•Photobacterium ganghwense K3b showed a significant degradation percentage of methyl orange, congo red, crystal violet and for malachite green.•Experimental design and RSM indicated that peptone concentration and pH were the most important factors linked to MG decolourization•Genomic analysis revealed the presence of several enzymes associated with chemicals and xenobiotics degradation.