Organisms which feed on microbes (bacteria and fungi) are termed microbivores. Most microbes, such as bacteria, are asexual. Plants have evolved efficient defense systems against pathogenic microbes. The low pH prohibits growth of many strains of pathogenic microbes. In dissecting cellulitis, pathogenic microbes are not usually present. Gases are produced in landfills due to the anaerobic digestion by microbes. They also help protect the body from the penetration of pathogenic microbes. The skin acts as a barrier to deter the invasion of pathogenic microbes. Glyphosate inhibits the EPSPS enzymes of different species of plants and microbes at different rates. This may involve removal of undissolved substances, dissolved substances and harmful microbes. Such places support unique biomes where many new microbes and other lifeforms have been discovered. Enzymes extracted from microbes can show PCB activity. Reduction of toxicity of hexavalent chromium involves methods using chemicals, microbes and plants. The mixture must be sterile in order to avoid introducing potentially harmful microbes. Boiling the wort ensures its sterility, helping to prevent contamination with undesirable microbes.