Enhanced production of di-(2-ethylhexyl) phthalate (DEHP) by Bacillus subtilis AD35 using response surface methodology (RSM)

Abstract

Our previous study demonstrated that a new Bacillus subtilis AD35 was the first Bacillus sp. so far possessing the capability to produce the antibacterial compound di-(2-ethylhexyl) phthalate (DEHP) [Lotfy WA, Mostafa SW, Adel AA, et al. Production of DEHP by Bacillus subtilis AD35: isolation, purification, characterization and biological activities. Microb Pathog. 2018;124:89-100]. In this study, we investigate the process parameters influencing DEHP production by B. subtilis AD35. The best culture medium, carbon and nitrogen source that significantly affected DEHP synthesis were beef-yeast-peptone medium, starch and L-asparagine, respectively. A fractional factorial design (FFD) was applied to screen the fermentation conditions affecting DEHP formation. Agitation rate, inoculum size and sodium chloride concentration were found to be the major factors affecting the synthesis of DEHP. Sequentially, response surface methodology (RSM) was implemented and a polynomial model was developed to predict maximum DEHP activities against Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Salmonella typhimurium, Staphylococcus aureus, Staphylococcus epidermidis, Listeria monocytogenes, Pseudomonas aeruginosa and Aeromonas hydrophila. At optimized conditions, agitation rate, 220 rpm; inoculum size, 0.075% (v/v) and sodium chloride concentration, 0.75% (w/v), DEHP activity markedly increased to 24.7 AU, which represents an approximately 707% increase when compared to the pre-optimized conditions. The work reported here represents the first optimization of the process parameters influencing DEHP synthesis by B. subtilis AD35. ARTICLE HISTORY

Biosynthesis of Silver Nanoparticles by Aspergillus terreus: Characterization, Optimization, and Biological Activities

“…Design of experiments (DOE) such as fractional factorial designs are sets of statistical and mathematical tools used for analysis and modeling of the processes where the response is influenced by several variables (Lotfy et al, 2018a). DOE are generally used to identify the most significant parameters in the bioprocess and to predict the optimal conditions (El-Helow et al, 2019;Lotfy et al, 2019). DOE are more effective, reliable and consume less materials, time, and effort to determine the near optimum settings for each variable.…”

Bioconversion of waste glycerol into viscosinamide by Pseudomonas fluorescens DR54 and its activity evaluation

“…RSM methodologies have been used for a multitude of successful scientific applications, including designing culture media composition and cultivation parameters for various biotechnological processes, for example, the biosynthesis of antimicrobial di-(2-ethylhexyl) phthalate (DEHP) by Bacillus subtilis 33 . Here, a combination of OVAT methodology, Plackett–Burman design for the screening of influential variables, and Box–Behnken design for the non-linear modeling of three independent variables allowed us to successfully establish optimal culture conditions that translated into nearly two-fold DEHP activity.…”

Bioactivity study and metabolic profiling of Colletotrichum alatae LCS1, an endophyte of club moss Lycopodium clavatum L.

“…1–14) sources are popular patterns for fermentation technology to achieve economically feasible and efficient situations [ 67 – 69 ]. Xenorhabdus bovienii and Bacillus subtilis AD35 were optimized using response surface methodology and antibiotic productions (xenortides, xenematide, xenoxoumacin, xenorhabdins, xenocoumacin, nematophin and di-(2-ethylhexyl) phthalate (DEHP) respectively) were enhanced remarkably [ 70 , 71 ].…”