The large scale production of organic acids by micro-organisms 119 You should note that the figure in SAQ 5. 1 is a simple outline as fermentations generall have more steps than indicated; for example many have a multiple purification step. If the product were the whole cell for example in single cell protein processes)then intracellular compound then some stage of cell ary. if the required product were ification of the cell biomass would be leakage would be essential 5.1.2 Organic acids relevant to this Chapter Table 5.1 shows the organic acids relevant to this Chapter together with the usual substrate, the micro-organisms employed to produce them and finally the potential end uses Such acids are often grouped into two broad categories, those which are members of or related to the tCa cycle and secondly those which are oxidation products of glucose the carbon source for the latter group is usually quite specific, either glucose itself or a polysaccharide which yields glucose easily. The carbon source for the former group can be much more diverse and/or example: glucose or its poly (molasses, starches); byproducts of industry(methanol, methane); waste products of ndustry (sulphite waste liquor from paper manufacture) or plant waste (lignins, cellulose derivatives). Acetate lactate and some amino acids however do not readily fit into either of the group organic acid substrate producer end use(s) micro-oro citric acid s) Aspergillus niger Flavouring for beverages and confectionery. Pharmaceutical food syrups, resins, dye mordants, antifoaming agents, sequestering ager malic acid ucose Lactobacillus brevis Food and drink manufacture Rhizopus delemar Used in the plastics industry and to a lesser extent. in the food industry ediate for organic illus spp syntheses, eg acrylic resins gluconic acid glucose Aspergillus niger Pharmaceutical industry and as a washing and softening agent preventing a build up of ethanol lactic acid lactose Lactic acid bacteria Dairy industry as a preservative/flavour enhancer Table 5. 1 Example of organic acids produced commercially by micro-organisms; organic acie considered in this chapter are labelled with. A related acid, a-oXoglutaric acid, is easy to produce microbiologically but has no current end use; succinic acid is produced chemically. Amino acids are beyond the scope of this chapter a detailed study of the amino acids is beyond the scope of this Chapter However, industrial production of amino acids is considered in Chapter 8 of this textThe large scale produdion of organic acids by microorganisms 119 You should note that the figure in SAQ 5.1 is a simple outline as fermentations generally have more steps than indicated; for example many have a multiple purification step. If the product were the whole cell (for example in *e cell protein processes) then purification of the cell biomass would be necessary. If the required product were an intracellular compound then some stage of cell breakage would be essential. 5.7.2 Organic acids relevant to this Chapter Table 5.1 shows the organic acids relevant to this Chapter together with the usual substrate, the miao-organisms employed to produce them and finally the potential end uses. Such acids are often grouped into two broad categories, those which are members of or related to the TCA cycle and secondly, those which are oxidation pducts of glucose. The carbon source for the latter group is usually quite specific, either glucose itself or a polysaccharide which yields glucose easily. The carbon source for the former group can be much more diverse and/or complex, for example: glucose or its polymers (molasses, starches); byproducts of industry (methanol, methane); waste products of industry (sulphite waste liquor from paper manufacture) or plant waste (lignins, cellulose derivatives). Acetate, lactate and some amino acids however do not readily fit into either of the groups. organic acid substrate producer end use(s) micro-organism citric acid sugar@) Aspergillus niger malic acid glucose Lactobacillus brevis fumaric acid glucose Rhizopus delemr itaconic acid glucose Aspergillus terreus gluconic acid glucose Aspegillus nger other Aspergillus spp Gluconobacter suboxidans acetic acid ethanol Acetobacter aceti lactic acid lactose Lactic acid bacteria Flavouring for beverages and confectionery. Pharmaceutical food syrups, resins, dye mordants, antifoaming agents, sequestering agents. Food and drink manufacture Used in the plastics industry and, to a lesser extent, in the food industry Intermediate for organic syntheses, eg acrylic resins Pharmaceutical industry and as a washing and softening agent preventing a build up of scale. Retards setting of building materials. Vinegar, food industry Dairy industry as a presewativenlavour enhancer Table 5.1 Example of organic acids produced commercially by micro-organisms; organic acids considered in this chapter are labelled with *. A related acid, a-oxoglutaric acid, is easy to produce microbiologically but has no current end use; succinic acid is produced chemically. Amino acids are beyond the scope of this chapter. A detailed study of the amino acids is beyond the scope of this Chapter. However, industrial production of amino acids is considered in Chapter 8 of this text