taguchi method

The native sponges of Persian Gulf are unique species facing difficult climate conditions and environmental contamination. It is necessary to investigate these native sponges because global warming most probably destroyed many of these creatures. Therefore, the study of the microorganisms associated with sponges will introduce new bacterial strains with various industrial and environmental applications and, in this way, a part of the Persian Gulf biodiversity will be preserved for posterity. The aim of this study was the isolation and molecular identification of bacteria associated with the ability of biodegrading crude oil from the native sponges of the Persian Gulf. Also, optimization of crude oil biodegradation was done for one of the most efficient bacterial strains. Isolated species were compared in terms of E24 index and growth rate in a culture medium containing at least 2% of oil as the sole carbon source. Molecular identification was done for five bacterial strains. Using the Taguchi experimental design, the effects of 4 factors, namely, carbon source auxiliary, organic and inorganic nitrogen sources, salinity and pH, were evaluated at 3 levels. GC-Mass analysis was performed on the remaining oil in the culture medium.. In the initial screening of two native species of sponges, 22 bacterial strains were isolated which were capable of decomposing oil. Five bacterial strains showed the best results and were recorded in NCBI with access numbers KY283126, KY283128, KY285290, KY285289, and KY285288. Brevibacterium sp. (KY283128) showed the highest level of oil degradation (about 97%) and growth rate. The results showed that the optimal oil degradation occurs in the absence of carbon source auxiliary, at 0.5% of salinity, with NH4 Cl as the nitrogen source and at a pH of 6.5. This bacterial strain can be used for biodegradation in oil-contaminated areas and oil refineries. By isolating the oil degrading gene in this bacterial strain and cloning it in other bacterial strains, the efficiency of eliminating oil contamination can be increased.

In this study, the feasibility of cruxrhodopsin (CR) production as a multifunctional nanoparticle was investigated and optimized by Halorculasp. IRU1, a novel halophile Archaea isolated from Urmia Lake, Iran in batch experiments. In this case, Taguchi method was used for effect measurement of three important factors (petrochemical wastewater, yeast extract and KH2PO4) on CR production. Results illustrated that the petrochemical wastewater concentration was the meaningful factor in CR synthesis. The optimum factor levels for petrochemical wastewater concentration, yeast extract and KH2PO4 were 2% (w/v), 0.2% (w/v) and 0.004% (w/v), respectively. Also, under these conditions, the predicted value for CR production was about 44.24%. Therefore, this investigation demonstrated that Haloarcula sp. IRU1 has a high potential for synthesis of CR from petrochemical wastewater.

Since the wound infections caused by gram positive and negative bacteria are very common, application of Nanocrystalline silver in wound healing bands is recently of one of points of research interests. The epithelization effect and control of wound infection are the most important factors for selection of disinfecting factors in these bands. This study was performed to produce nanocrystalline silver bands and to investigate their efficiency on control of selected gram positive and negative bacteria.
In this study, silver nanocrystalline dressing was produced using nylon dressing and silver ions. Thereafter, we evaluate its antibacterial effect against Staphylococcus aureus and Escherichia coli. The experiments were designed based on Taguchi method for investigation different parameters on antimicrobial effect of silver dressing.
The silver dressing showed an impressive effect on inhibition of the growth of mentioned bacteria and leads to the inhibition zone diameter of 5.5 cm around the dressing pieces. AgNO3 was the most important parameter in determination of the antimicrobial effect of silver dressing (approximately 65% efficiency).
Silver nanocrystalline dressing was effective on inhibition of microorganisms growth. Furthermore, application of Taguchi method was highly effective in optimization process of this investigation.

Halophilic and halotolerant microorganisms are good candidates for decolorization of azo dyes which are routinely used in the dyeing process in textile industries. In this paper, theoptimization of biological decolorization of synthetic dye solutions containing Remazol Black B by the previously isolated halophilic bacterium Halomonas sp. D2 is investigated. In a primary investigation using a one-factor–at-a-time method, temperature, initial pH of the solution, and concentrations of glucose, yeast extract, and sodium chloride were chosen for optimizing dye removal using the Taguchi method. Based on the statistical analysis of the results, the most significant parameter by far was the yeast extract concentration which accounted for 72.67% of the total effect, followed by pH (11.84%) and the NaCl concentration (8.90%). The optimized conditions for dye removal were predicted to be a temperature of 35°C, an initial pH of 10, glucose concentration of 1% (w/v), yeast extract concentration of 1% (w/v), and sodium chloride of 10% (w/v). Under these conditions, 95% decolorization was achieved in confirming experiments.