A Comparative Study on Chemical Characterization and Properties of Surface Active Compounds From Gram-positive Bacillus and Gram-negative Ochrobactrum Strains Utilizing Pure Hydrocarbons and Waste Mineral Lubricating Oils

Mineral lubricating oils are widely used in various industrial sectors for their applications in maintenance and functioning of machineries. However, indiscriminate dumping of these used oils has resulted in polluting the natural reservoirs which subsequently destroys ecological balance. Bacteria can emulsify or lower surface tension between phases of immiscible substrates and can acquire them as their carbon and energy sources. Such a phenomenon is mediated by synthesis of extracellular polymeric substances which can function as eminent surface active compounds based on their surfactant or emulsifying nature. The comparison between bacterial strains (Gram-positive Bacillus stratosphericus A15 and Gram-negative Ochrobactrum pseudintermedium C1) on utilisation of pure straight chain hydrocarbons, waste mineral lubricating oils as sole carbon source and chemical characterization of the synthesized surface active compounds is studied. Characterization analysis by Ultraviolet Visible spectrophotometry, Fourier-transform infrared spectroscopy, Nuclear Magnetic Resonance spectroscopy, Carbon-Hydrogen-Nitrogen analysis has given detailed structural elucidation of surface active compounds. The contrasting nature of bacterial strains in utilisation of different hydrocarbons of spindle oil was observed in Gas Chromatography-Mass Spectroscopy. The variation between both strains in utilisation of hydrocarbons can be manifested in a difference in chemical structure and properties of the synthesized surface active compounds. Scanning Electron Microscopy gives detailed insight into the difference in morphological nature of the compounds. The utilisation of these lubricating oils can address waste disposal problem and offer an economical feasible approach for bacterial synthesis of surface active compounds. Additionally, their distinctive nature and properties can maneuver applications in bioremediation of toxic environmental pollutants and as biomaterials in pharmaceutics.

BIOSURFACTANTS SYNTHESIS BY PSEUDOMONAS AERUGINOSA BACTERIA ISOLATED FROM THE SURFACE OF MUSSELS OF THE BLACK SEA

Aim. Establishing of the ability to synthesize surface-active compounds by Pseudomonas aeruginosa bacteria isolated from the surface of Black Sea mussels. Methods. During the research several marine Pseudomonas spp strains isolated from petroleum hydrocarbon contaminated areas of Black Sea wereused: P. aeruginosa M1, P. aeruginosa M4 and P. aeruginosa PA01 as reference strain in suspension and biofilm cultures (LB and Giss media). Cultivation of Pseudomonas aeruginosa strains was performed at 37 °C for 120 and 168 hours. Planktonic culture growth was determined spectrophotometrically on the wave length 600 nm. Biofilm mass was determined spectrophotometrically on the wave length 592 nm by CV-test. The presence of surface-active compounds was determined in a drop test. The quantitative content of rhamnolipids was evaluated by the color reaction of rhamnose with orcin. Results. P. aeruginosa strains M1 and M4 isolated from Black Sea mussel’s surfaces synthesize 25% and 66% more surfactants than the reference strain PA01. All strains in Giss medium synthesized 10–20 times less rhamnolipids than in LB medium. In biofilm cultures the same biosurfactant synthesis dependence on the composition of the nutrient medium is observed as in suspension cultures. According to the intensity of rhamnolipid production in biofilm cultures, the studied strains can be arranged in the following row: P. aeruginosa M4 > P. aeruginosa M1 >> P. aeruginosa PA01.Conclusions. The strains of P. aeruginosa isolated from the Black Sea are more efficient producers of rhamnolipids than the reference strain of P. aeruginosa PA01; the intensity of biosynthesis of surfactants significantly depends on the composition of the nutrient medium and the method of cultivation.

Antiviral Activity of the Rhamnolipids Mixture from the Antarctic Bacterium Pseudomonas gessardii M15 against Herpes Simplex Viruses and Coronaviruses

Emerging and re-emerging viruses represent a serious threat to human health at a global level. In particular, enveloped viruses are one of the main causes of viral outbreaks, as recently demonstrated by SARS-CoV-2. An effective strategy to counteract these viruses could be to target the envelope by using surface-active compounds. Rhamnolipids (RLs) are microbial biosurfactants displaying a wide range of bioactivities, such as antibacterial, antifungal and antibiofilm, among others. Being of microbial origin, they are environmentally-friendly, biodegradable, and less toxic than synthetic surfactants. In this work, we explored the antiviral activity of the rhamnolipids mixture (M15RL) produced by the Antarctic bacteria Pseudomonas gessardii M15 against viruses belonging to Coronaviridae and Herpesviridae families. In addition, we investigated the rhamnolipids’ mode of action and the possibility of inactivating viruses on treated surfaces. Our results show complete inactivation of HSV-1 and HSV-2 by M15RLs at 6 µg/mL, and of HCoV-229E and SARS-CoV-2 at 25 and 50 µg/mL, respectively. Concerning activity against HCoV-OC43, 80% inhibition of cytopathic effect was recorded, while no activity against naked Poliovirus Type 1 (PV-1) was detectable, suggesting that the antiviral action is mainly directed towards the envelope. In conclusion, we report a significant activity of M15RL against enveloped viruses and demonstrated for the first time the antiviral effect of rhamnolipids against SARS-CoV-2.

Trichoderma citrinoviride: Anti-Fungal Biosurfactants Production Characteristics

The mechanism of direct impact of Trichoderma fungi on other organisms is a multilayer process. The level of limiting the growth of other microorganisms is determined by the strain and often by the environment. Confirmation of the presence of extracellular biosurfactants in certain strains of Trichoderma considered as biocontrol agents was regarded as a crucial topic complementing the characterization of their interactive mechanisms. Selected strains of T. citrinoviride were cultured in media stimulating biosurfactant biosynthesis, optionally supplemented with lytic enzyme inducers. Results confirmed the anti-fungal properties of surface-active compounds in the tested culture fluids. Preparations that displayed high fungal growth inhibition presented marginal enzymatic activities of both chitinases and laminarinases, implying the inhibitory role of biosurfactants. Fractions from the foam of the culture fluid of the C1 strain, cultured on Saunders medium, and HL strain on MGP medium, without an additional carbon source, exhibited the most prominent ability to inhibit the growth of phytopathogens. Filamentous fungi capable of producing fungicidal compounds, including surfactants, may find applications in protecting the plants against agri-food pathogenic molds.

FILM-FORMING PROPERTIES OF STREPTOCOCCUS SPP. IN THE PRESENCE OF ANTISEPTICS BASED ON CATIONIC SURFACE-ACTIVE COMPOUNDS

According to the American National Institutes of Health, about 80% of bacterial infections are film-associated that impedes their treatment and prevention. Scientists emphasize that the frequent chronicity of diseases associated with film-forming pathogens, and their significant resistance to antimicrobials today poses the major health problem worldwide. The aim of this study is to determine the film-forming properties of clinical isolates of Streptococcus spp. isolated from patients having odontogenic purulent-inflammatory diseases of the soft tissues of the maxillofacial area in the presence of antiseptics decasan and chlorhexidine. Materials and methods. The clinical isolates of S. warneri (n = 3), S. sanguinis (n = 4), S. sobrinus (n = 4), S. mitis (n = 4), S. salivarius (n = 5) were the objects of the study. To identify film-forming properties of the clinical isolates, a spectrophotometric method according to G.D. Christensen was applied. The antiseptics based on cationic surfactants as Decasan 0.2 (LLC "Yuri-Pharm", Kyiv, Ukraine) and chlorhexidine bigluconate 0.05 (Chlorhexidine-KR®, PJSC "Chimpharmzavod" Red Star ", Kharkiv, Ukraine) were used. Results and discussion. The study has shown that S. sorbinus and S. sanguinis have high film-forming properties; S. mitis and S. warneri demonstrate moderate film-forming properties. The antiseptic Decasan helped to reduce the film formation by all investigated isolates of Streptococcus spp. The effect of chlorhexidine on the ability of microbial isolates to produce biofilms was slightly lower compared to Decasan; moreover, in the case of S. mitis species, chlorhexidine even enhances film-forming properties. Conclusion. Streptococci of the viridans group, which are isolated from patients having odontogenic purulent-inflammatory diseases of the soft tissues of the maxillofacial area, have different film-forming properties. Decasan is more effective against the film formation by streptococci compared to Chlorhexidine.

SURFACTANT MATERIAL PROPERTIES AND CORONAVIRUS SURFACE: A SURFACE INTERACTION FOR COVID-19 TREATMENT AND VACCINATION

Generally, the structural components of infectious diseases causing viruses like coronavirus, Ebola virus, etc., are mainly focused on developing effective treatment and vaccines. Meanwhile, the spike proteins play a major role in knowing the profound way out to curtail the respective infectivity. S1 and S2 act as the two main subunits to render prime significance to reveal the interaction of surface-active agents in this context. Keeping in view the importance of surfactants in developing effective treatment and vaccine for the coronavirus infectious disease-2019 (COVID-19), this article describes the surface chemistry of this quest. The surface action being the main mode of infectivity can thus be halted by using surface-active compounds (surfactants). Therefore, this review emphasizes the sound role of surface action linked with COVID-19 treatment and vaccination.

Recent Development on Herder Commercialization

Herders (also known as surface collecting agents) are made of surface active compounds (surfactants). They reduce the surface tension of water and thereby change the spreading behavior of immiscible liquids, such as an oil slick, floating on the surface. Oil slicks that have spread too thin to burn can be re-thickened if herders are sprayed on the water surface around a slick. Once the slick is thickened, it is amenable to in situ burning without the need for fire-resistant boom. Herders are listed as surface collecting agents on the National Contingency Product Schedule administered by the US Environmental Protection Agency (USEPA, 2019) for use in US waters. Herders are commercially available and oil spill response organizations have the capability to utilize herders. A new joint industry / government agency project was recently initiated to develop a novel herder delivery and ignition system. The initial plan is to develop a remotely operated surface vehicle (RSV) that will deliver herder from an onboard reservoir and a system to ignite herded slicks. The RSV we are developing has 10–12 hours of operation time, a range of 500 miles and can travel at speeds of up to 65 miles/hour. The RSV can be deployed from a helicopter that has a cargo hook, a boat, and potentially a fixed-wing aircraft that has an appropriately sized hatch. The vision is rapid deployed to a remote spill location using a helicopter (or a fixed-wing aircraft) and operated from this platform until a response vessel arrives on the scene. The response vessel can then take over RSV control freeing the aircraft for other duties. This paper will describe the planned development and testing of the RSV and other progress toward herder commercialization.