Economic importance of Bacteria

Bacteria have a genuinely two-sided economic impact. On the beneficial side, they underpin soil fertility through ammonification (Bacillus ramosus, Bacillus mycoides converting dead organic matter into ammonia/ammonium salts), nitrification (Nitrobacter, Nitrosomonas converting ammonium salts to nitrites and nitrates) and nitrogen fixation (Azotobacter, Clostridium, Rhizobium converting atmospheric nitrogen into organic nitrogen); they are the source of major antibiotics (e.g. Streptomycin from Streptomyces griseus, treating tuberculosis and pneumonia; Aureomycin from Streptomyces aureofaciens; Chloromycetin from Streptomyces venezuelae, treating typhoid; Bacitracin and Polymyxin from Bacillus species); and they drive whole industries, converting milk into lactic acid, butter, cheese, curd and yoghurt (Streptococcus lactis, Lactobacillus species), fermenting molasses into vinegar (Acetobacter aceti) and into butyl/methyl alcohol and acetone (Clostridium acetobutylicum), separating plant fibres by retting (Clostridium tertium), synthesising vitamin K, B-complex and B2 (E. coli, Clostridium acetobutylicum), and giving tea and tobacco their characteristic aroma during curing. On the harmful side, bacteria cause serious disease in plants (e.g. bacterial blight of rice by Xanthomonas oryzae, fire blight of apple by Erwinia amylovora, citrus canker by Xanthomonas citri), in farm …