Actinomycete mycelium in biological treatment
Except for a few autotrophic strains such as autotrophic Streptomyces, the vast majority are heterotrophic. The nutritional requirements of heterotrophic bacteria vary widely, some can utilize simple compounds, while others require complex organic compounds. They can utilize different carbohydrates, including sugar, starch, organic acids, cellulose, hemicellulose, etc. as energy sources. The best carbon sources are glucose, maltose, dextrin, starch, and glycerol, followed by sucrose, xylose, raffinose, alcohol, and organic acids. Among organic acids, acetic acid, lactic acid, citric acid, succinic acid, and malic acid are easy to utilize, while oxalic acid, tartaric acid, and hippuric acid are difficult to utilize. Some actinomycetes can also utilize chitin, hydrocarbons, tannins, and even rubber.
In terms of nitrogen nutrition, protein, protein has peptone and some amino acids are the most suitable, followed by nitrate? Ammonium and vegetarian. Except for Nockar'sbacteriaIn addition, most actinomycetes can use casein and can liquefy gelatin. Like other organisms, the growth of actinomycetes generally requires K, Mg, Fe, Cu and Ca, among which Mg and K have significant effects on mycelium growth and antibiotic production. The mineral nutrients required for the production of various antibiotics are not exactly the same. For example, Streptomyces freundii produces neomycin, which requires Zn, while Mg, Fe, Cu, Al and Mn and so on do not work. Co is an essential element for the production of vitamin B12 by actinomycetes. When the medium contains 1 or 2 ppm of Co, it can increase the vitamin production of Streptomyces grayscale by three times. If the content of Co in the medium is as high as 20-50 ppm, it will produce toxic effects. In addition, Co also has the function of promoting spore formation.
Most actinomycetes are aerobic, and only some species are trace aerobic bacteria and anaerobic bacteria. Therefore, adequate ventilation must be ensured during the industrial fermentation production of antibiotics; temperature also affects the growth of actinomycetes. The optimal growth temperature of most actinomycetes is 23-37 ° C, and the growth temperature range of high-temperature actinomycetes is 50-65 ° C, and many species still grow well below 20-23 ° C. Actinomycete mycelium has stronger drying resistance than bacterial nutrients, and many species can survive for about one and a half years in the dryer of CaCl2 and H2SO4.
Actinomycetes can decompose many organic compounds, including complex compounds such as aromatic compounds, paraffin, rubber, cellulose, wood, and some highly toxic compounds such as cyanide. Therefore, actinomycetes not only play an active role in the natural material cycle, but also in the biological treatment of sewage and organic solid waste, and can also promote the formation of soil agglomerate structure to improve soil.
