Use of Ca-alginate immobilized Pseudomonas aeruginosa for repeated batch and continuous degradation of Endosulfan

Abstract

The current investigation is taken up with the aim of studying repeated batch and continuous degradation of Endosulfan, using Ca-alginate immobilized cells of Pseudomonas aeruginosa isolated from an agricultural soil. The work involves the study of genes and enzymes involved in the degradation of the pesticide and was carried out with an objective of reducing the toxicity of Endosulfan by degrading it to less toxic metabolites. The long-term stability of Endosulfan degradation was studied during its repeated batch degradation, carried out over a period of 35 days. Immobilized cells of Ps. aeruginosa were able to show 60 % degradation of Endosulfan at the end of the 35th cycle with a cell leakage of 642 × 104 Cfu/mL. During continuous treatment, with 2 % concentration of Endosulfan, 100 % degradation was recorded up to 100 mL/h flow rate and with 10 % concentration of the Endosulfan, and 100 and 85 % degradation was recorded at 20 mL/h flow rate and 100 mL/h flow rate, respectively. After degradation of Endosulfan, products were extracted from a large amount of spent medium using two volumes of ethyl acetate and subjected to the LC–MS analysis. Endosulfan lactone and Endosulfan ether were the products of degradation detected by the LCMS analysis. Plasmid curing experiments indicated that genes responsible for the degradation of Endosulfan are present on the chromosome and not on the plasmid, as growth of Ps. aeruginosa was observed on modified non-sulfur medium with Endosulfan after the plasmid was cured with ethidium bromide. The results of PCR indicated that there is no amplified product of ~1350 bp expected for esd gene, in Ps. aeruginosa, although there were some non-specific bands. Enzymatic degradation studies indicated that the enzymes involved in the degradation of Endosulfan are intracellular. With this investigation, it was indicated that immobilized cells of Ps. aeruginosa have the potential to be used in the bioremediation of water contaminated with Endosulfan.

Performance of a continuous stirred tank bioreactor employing an immobilized actinobacteria mixed culture for the removal of organophosphorus pesticides

“…Therefore, efforts have been made to identify an appropriate bioreactor configuration to avoid and reduce the volume of wastewater containing pesticides prior to its final disposal (Gonzalez-Cuna et al 2016). Bioreactor configurations can include the use of immobilized microorganisms (Yadav et al 2014;Pradeep and Malavalli 2016), and the support material for cell immobilization is one of the main features that affects bioreactor configuration and performance (Cabrera-Orozco et al 2017). In this context, an evaluation of different supports must be conducted to obtain optimal colonization and activity of the microorganisms (Tarjányi-Szikora et al 2013) and therefore an appropriate reactor design.…”

Treatment of Pesticide-Contaminated Water Using a Selected Fungal Consortium: Study in a Batch and Packed-Bed Bioreactor

“…The immobilization of microbial cells has received considerable attention in the field of bioremediation and specifically in the treatment of pesticide wastewater [32][33][34][35]. Encapsulation provides microorganisms with a protective structure, making microorganisms less exposed, more stable, and more viable for a longer period, which facilitates the storage and handling of cultures [36].…”

Current status of pesticide effects on environment, human health and it’s eco-friendly management as bioremediation: A comprehensive review

“…Now, research has shifted to the use of microbial cells as CI, which protects and allows them to be reused. Such a strategy enhances the possibilities of techniques lasting and succeeding in a pesticide-contaminated environment for a long period and has been found suitable for pesticide biodegradation ( Colla et al, 2014 ; Pradeep and Subbaiah, 2016 ; Fernández-López et al, 2017 ; Conde-Avila et al, 2021 ).…”