Abstract
A Pseudomonas citronellolis strain was isolated from drilling waste (DW). This strain utilizes DW as the sole energy and carbon source to produce biosurfactants (BSs). The BS produced was thermally stable, amorphous and includes a peptide structure. FeSO4, FeCl3 and Fe(NO3)3 were supplemented at various concentration levels to assess possible enhancement of BS production and DW biodegradation. The limit concentration of Fe compounds between the increase in BS formation and microbial toxicity was 0.1 mM. FeCl3 enhanced DW biodegradation and more than doubled the BS formation yield, determining an optimization strategy for BS production. The BS was then partially purified and used against several Gram-negative and positive multi-drug resistant bacteria (such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli spp, Acinetobacter baumaniii, Enterococcus faecalis spp, Streptococcus pneumoniae, Staphylococcus aureus, Salmonella enterica). The minimum inhibitory concentration was defined at a range of 0.25 to 10 mg/mL. The antimicrobial properties of the partially purified BS established its effectiveness and suggested a down-stream processing cost reduction, as no additional purification steps were necessary. The study could lead to a sustainable low-cost bioprocess towards a circular bioeconomy because waste, a non-expensive substrate, is used; while the BS holds great potential as a novel compound with antibiotic and disinfectant-like action, following toxicity testing with human cells.
Highlights
Surfactants, which are surface active agents, are classified into two main categories: synthetic surfactants and biosurfactants
Synthetic surfactants are produced by organic chemical reactions, whereas biosurfactants are produced by biological processes of microorganisms [1]
It is likely that the presence of biocides in the drill cutting fluid (DCF) prevented the isolation of more than one microorganism
Summary
Surfactants, which are surface active agents, are classified into two main categories: synthetic surfactants and biosurfactants. Given the different types of BS-producing microbial species and BS chemical structures, microbial surfactants are separated into four main categories: (1) glycolipids, (2) phospholipids, (3) polymeric surfactants, and (4) lipoproteins and lipopeptides [5]. Due to their exceptional properties, BSs are being increasingly used in various fields including: pharmaceutical and food industries as emulsifiers; surfactants in laundry products by detergent-producing industries; biological control agents in heavy oil spill mobilization for the control of oil pollution, for cleaning of oil sludge at storage facilities, as well as in the bioremediation of oil contaminated soil and (microbial) enhanced oil recovery ((M)EOR)) [6]. Several BSs exhibit antibacterial, antifungal, anticancer and antiviral activities, which render them appropriate candidate molecules for applications in combating many infections, viruses and diseases [7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
