Galina Satchanska

By Galina Satchanska

This chapter focuses on methods of polyphenol isolation and on the antibacterial activity of different polyphenols found in herbs, spices, fruits and vegetables. Polyphenols are secondary metabolites which protect plants from different pathogens, such as viruses, bacteria, fungi, insects, and herbivores. Currently, about 9000 polyphenols found in more than 480 plants are known. Their amount fluctuates across different species and varieties. This chapter describes conventional and novel methods for extraction, the influence of the type of solvents, solvent concentration and temperature on the yield. The highest yield is obtained at 70% of methanol and ethanol, and at 90% of acetone. Extraction at 80°C leads to higher amounts of polyphenols than extraction at 100°C. Polyphenols are usually metabolized in the human liver but can also remain unaffected as they pass through the gastrointestinal tract. The main location for their uptake is the colon. They exhibit a wide range of antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus epidermidis, Klebsiella pneumoniae, E. coli, Listeria monocytogenes, Acinetobacter sp., Proteus sp., Micrococcus sp., and Bacillus sp. All these plants, rich in antimicrobial polyphenols, represent a promising and powerful source of highly effective novel antibacterial substances in the current era of ubiquitous antibiotic resistance.

Part of the book: Secondary Metabolites

By Galina Satchanska

This Chapter discusses the entrapment, growing and biofilm formation by an environmental bacterium immobilized in polyethyleneoxide cryogel to be applied in environmental biotechnology. The KCM-R5 bacterium was isolated from the heavy metal-polluted environment near a large Pb-Zn smelter, also producing precious metals in Bulgaria. Molecular-genetic analysis revealed affiliation with Pseudomonas rhodesiae. The strain is capable of growing in high concentrations of phenol and different phenol derivatives. Polyethylene oxide was found to be friendly and nontoxic to bacteria polymer enabling bacteria easy to penetrate in it and fast to grow. KCM-R5 biofilms were grown for 30 days in batch culture with phenol (300-1000 mg L−1) dissolved in the mineral medium. The bacterium was able to involve phenol in its metabolism and use it as a single carbon supplier. The results obtained in the study showed 98% phenol biodegradation using the biotech installation described. The proposed PEO cryogel-P. rhodesiae KCM-R5 bacterium biotech biofilter can be used for environmental biotechnology application in industrial wastewater detoxification.

Part of the book: Focus on Bacterial Biofilms