Response Surface Modeling for Co-Remediation of Cr⁶⁺and Pentachlorophenol byBacillus cereusRMLAU1: Bioreactor Trial and Structural and Functional Characterization by SEM-EDS and FT-IR Analyses

Abstract

This is the first report on optimization of process variables for simultaneous bioremediation of pentachlorophenol (PCP) and Cr 6C employing traditional and response surface methodology (RSM). In a one-factor-at-a-time approach, the effect of PCP level exhibited maximum bacterial growth and Cr 6C (82%) and PCP (91.5%) removal at initial 100 mg PCP L ¡1 with simultaneous presence of 200 mg Cr 6C L ¡1 within a 36-h incubation. However, at varied Cr 6C concentrations, maximum growth and Cr 6C (97%) and higher PCP (59%) removal were achieved at 50 mg Cr 6C L ¡1 with simultaneous presence of 500 mg PCP L ¡1 within a 36-h incubation. The Box-Behnken design suggested 100% Cr 6C and 95% PCP remediation at 36 h under optimum conditions of 75 mg PCP and 160 mg Cr 6C L ¡1 , pH 7.0, and 35 C; Cr 6C removal was further enhanced to 97% in bioreactor trial. Fourier transform infrared (FT-IR) analysis revealed the likely involvement of hydroxyl, amide, and phosphate groups in Cr 3C binding. Scanning electron microscopy and energy-dispersive x-ray spectroscopy (SEM-EDS) showed biosorption of reduced chromium on bacterial cell surface. This isolate can be employed for eco-friendly and effective in situ bioremediation of Cr 6C and PCP simultaneously.

The sustainable development goals in a bioremediation journal context: what a difference a year makes in a post COVID-19 world!

“…Metals (Okumus et al 2015;Dutta et al 2017;Aka and Babalola 2017), and hydrocarbons (Mutharasaiah et al 2011;Yao et al 2014;Suarez and Rifai 1999) have received much attention from Journal authors, as have agricultural practices and waste products (Ramarajan and Manohar 2017), manufacturing wastes (Khan et al 2014), and the abundance and biodegrading potential of marine organisms (Khosrowabadi and Huyop 2013). Models of various environmental mechanisms and processes were developed by a number of authors over the years (Farhan and Hatzinger 2009;Vaezihir et al 2012;Das Saha 2012;Tripathi and Kumar Garg 2014;Ling et al 2004) and others addressed solid wastes and their degradability using microorganisms (Garg and Gupta 2011). The depth and breadth of topics related to the SDGs listed above that have been studied by Journal authors since 1997 is very extensive and indicative of a keen interest in sustainability using biotechnology.…”