Q.Name the fungus used for the industrial production of citric acid, and state the raw material on which it is commonly grown at industrial scale.

Industrial microbial production uses purpose-built fermenters (bioreactors) to grow selected microbial strains under tightly controlled conditions of temperature, pH, nutrients and aeration, manufacturing valuable compounds at a scale and reliability impossible in an uncontrolled setting. Organic acids are a major category: Aspergillus niger yields citric acid, Lactobacillus yields lactic acid, and Clostridium butylicum yields butyric acid, all used as food acidulants or industrial feedstocks. Saccharomyces cerevisiae is grown industrially to produce bulk ethanol. Microbially produced enzymes -- lipases (used in detergents), pectinases (used to clarify fruit juice), and streptokinase from Streptococcus (used medically to dissolve blood clots after a heart attack) -- are manufactured the same way. More complex bioactive pharmaceuticals are also microbial products: the immunosuppressant cyclosporin A comes from Trichoderma polysporum, and cholesterol-lowering statin drugs were first obtained from Monascus purpureus. The unifying idea is that finding or engineering an organism that already makes a needed molecule, then growing it at scale, is often far more efficient than synthesising the same molecule chemically from scratch.