Bacteria nutrient requirements

Biological denitrification is more complex to operate because it relies on the capabilities of active bacteria, but effectively convert nitrate to not toxic chemicals (N2). It can be subject to transient states generating malfunctions and requires thus greater care. Biological denitrification produces bacteria sludge, requires chemical additives (carbon source and other nutrients for bacteria) and especially requires large installations. 

Lactic acid is a major end product from fermentation of a carbohydrate by lactic acid bacteria (Tormo and Izco, 2004). However, lactic acid can be produced commercially by either chemical synthesis or fermentation. The chemical synthesis results in a racemic mixture of the two isomers whereas during fermentation an optically pure form of lactic acid is produced. However, this may depend on the microorganisms, fermentation substrates, and fermentation conditions. Lactic acid can be produced from renewable materials by various species of the fungus Rhizopus. This has many advantages as opposed to bacterial production because of amylolytic characteristics, low nutrient requirements, and the fungal biomass, which is a valuable fermentation by-product (Zhan, Jin, and Kelly, 2007). 

If fluid velocity is low (less than 1.5 m/s), biofilm can be established. If, on the other hand, it is moving sufficiently fast, due to turbulence thus produced, the food required by the bacteria (nutrient) can reach bacteria more efficiently due to enhanced mass transfer. 

Owing to the absence of toxicity and valuable biotechnological properties, propionic acid bacteria are widely used in industry (food industry, vitamin B]2 production). Genetic approaches may help increase strain productivity, change nutrient requirements, confer phage resistance. 

Bacteria that require free o gen to metabolize nutrients. 

It is significant that attention first became focussed on the nutrient requirements of those bacteria which are among the most exacting in this respect. This was either because the complex media they required for growth were easily injured in preparation (owing to the presence of essential labile substances) and thus rendered nutritionally deficient, or because unusual nutrient supplements were required. Thus the question of the nutrient requirements of bacteria became differentiated as a particular problem of bacteriology in much the same way as the human and animal vitamin problem forced itself on the attention of biochemists, namely as a problem of nutritional deficiency. 

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