EXTRACTION, CHARACTERIZATION, AND ANTIMICROBIAL ACTIVITY OF F7 BIOSURFACTANT FROM BACILLUS CLAUSII AGAINST ORAL PATHOGEN KEY PLAYERS Introduction: Biosurfactants are surface-active molecules produced by various microorganisms. It holds exceptional properties, including its capacity to lower surface tension, antiadhesive activity, non-toxicity, biodegradability, and antimicrobial activity. Objectives: This study investigated the production, characteristics, and antimicrobial potential of biosurfactants extracted from Bacillus clausii, isolated from a crude oil sample obtained from a natural oil reservoir. Methods: Biosurfactant was extracted using the chloroform-methanol extraction method. Characterizations were assessed through Fourier-Transform Infrared Spectroscopy (FTIR), determination of surface tension, Critical Micelle Concentration (CMC), and emulsification index. Antimicrobial activity was determined by the Minimum Inhibitory Concentration (MIC) evaluation against Streptococcus mutans ATCC 25175, Enterococcus faecalis ATCC 24212, and Candida albicans ATCC 14503 using the microdilution method. Results: The biosurfactant extraction yielded at 1.6 mg mL-1, and was labelled as F7 biosurfactant. FTIR analysis revealed that the F7 biosurfactant belonged to the lipopeptide group, as evidenced by the presence of an aliphatic chain (CH3 and CH2). It exhibited a surface tension of 12.0 mN m-1, a CMC of 157.5 mg L-1, and an emulsification index of 56.5%. The MIC for each tested organism was 0.2 mg/mL-1, 0.4 mg/mL-1, and 0.8 mg/mL-1 with inhibition percentages of 3.20%, 4.03%, and 7.87% against S. mutans, E. faecalis, and C. albicans, respectively. Conclusions: The antimicrobial activities of the F7 biosurfactant demonstrated dose-dependent. These findings suggest that increasing the F7 biosurfactant concentration could lead to a more effective antimicrobial effect, making it a potential antimicrobial agent for oral applications.

Candida species have been associated with the emergence of strains resistant to selected antifungal agents. Plant products have been used traditionally as alternative medicine to ease mucosal fungal infections. This study aimed to investigate the effects of Piper betle extract on the growth profile and the ultrastructure of commonly isolated oral candidal cells. The major component of P. betle was identified using liquid chromatography-mass spectrophotometry (LC-MS/MS). Seven ATCC control strains of Candida species were cultured in yeast peptone dextrose broth under four different growth environments: (i) in the absence of P. betle extract; and in the presence of P. betle extract at respective concentrations of (ii) 1 mg⋅mL(-1); (iii) 3 mg⋅mL(-1); and (iv) 6 mg⋅mL(-1). The growth inhibitory responses of the candidal cells were determined based on changes in the specific growth rates (µ). Scanning electron microscopy (SEM) was used to observe any ultrastructural alterations in the candida colonies. LC-MS/MS was performed to validate the presence of bioactive compounds in the extract. Following treatment, it was observed that the µ-values of the treated cells were significantly different than those of the untreated cells (P<0.05), indicating the fungistatic properties of the P. betle extract. The candidal population was also reduced from an average of 13.44×10(6) to 1.78×10(6) viable cell counts (CFU)⋅mL(-1). SEM examination exhibited physical damage and considerable morphological alterations of the treated cells. The compound profile from LC-MS/MS indicated the presence of hydroxybenzoic acid, chavibetol and hydroxychavicol in P. betle extract. The effects of P. betle on candida cells could potentiate its antifungal activity.
Antifungal Agents ; pharmacology ; Candida ; drug effects ; growth & development ; ultrastructure ; Candida albicans ; drug effects ; growth & development ; ultrastructure ; Candida glabrata ; drug effects ; growth & development ; ultrastructure ; Candida tropicalis ; drug effects ; growth & development ; ultrastructure ; Chromatography, Liquid ; methods ; Colony Count, Microbial ; Culture Media ; Eugenol ; analogs & derivatives ; analysis ; Humans ; Hydroxybenzoates ; analysis ; Microbial Viability ; drug effects ; Microscopy, Electron, Scanning ; Mouth ; microbiology ; Phytotherapy ; Piper betle ; chemistry ; Plant Extracts ; analysis ; pharmacology ; Spectrophotometry ; methods ; Tandem Mass Spectrometry ; methods ; Time Factors