Q.Give the microbial source of Vit. B12.

Beyond everyday food, industrial-scale fermentation in large vessels called fermenters is used to manufacture alcoholic beverages, organic acids, vitamins, enzymes, antibiotics and plant growth hormones. Alcoholic beverages — a practice in India since Vedic times (5000–7000 BC) — are produced when yeasts, especially Saccharomyces cerevisiae var. ellipsoidis (brewer's yeast), ferment malted cereals or fruit juices into ethanol, giving wine and beer (undistilled) or whiskey, brandy and rum (distilled), typically in a tubular tower fermenter; regional examples include a fermented palm-sap drink from coastal South India and Goa's cashew-fruit wine, fenny. Organic acids produced microbially include citric acid and gluconic acid (both from Aspergillus niger), fumaric acid (from Rhizopus arrhizus) and acetic acid/vinegar (from Acetobacter aceti). Vitamins that cannot be made by the human body (except vitamin D) are manufactured using microbes, including vitamin B2 (Neurospora gossypii or Eremothecium ashbyi), vitamin B12 (Pseudomonas denitrificans) and vitamin C (Aspergillus niger). Antibiotics — mostly secondary metabolites that inhibit competing microbial pathogens — include chloromycetin (Streptomyces venezuelae), erythromycin (Streptomyces erythreus), penicillin (Penicillium chrysogenum), streptomycin (Streptomyces griseus), griseofulvin (Penicillium griseofulvum), bacitracin (Bacillus licheniformis) and oxytetracycline/terramycin (Streptomyces aurifaciens). Enzymes produced commercially include invertase (Saccharomyces cerevisiae), pectinase (Sclerotinia …