4.4 Substrates for SCP production For a micro-organism to grow it must be supplied with all the nutrients required for cell material and energy pre The physiological types of organism used in sCP production and their corresponding shown in Table 4.1. Photosynthetic bacteria utilise CO from the atmosphere and nitrate in inorganic salts or natural ground water media. algae are similar, growing on nitrate, ammonia or ammonium salt as nitrogen source. Some can also be grown as heterotrophs, in the dark, using sugars as sources of carbon and energy. Heterotrophic bacteria and fungi for SCP are grown on a variety of organic substrates, serving as both carbon and energy sources. Some organisms have additional requirement for growth factors, such as vitamins. For yeast, the substrate is in the form f sugars, as yeast cells cannot break down polysaccharides, whereas filamentous fungi hemiceulb may in addition be able to use starch oy secreting, amylases ), pectin(by secreting pectinases)and cellulosic material (by secreting cellulases and hemicellulases). Waste hemicellulases containing cellulosic material is in solid rather than in liquid form. Processes have also been developed with yeasts growing on n-paraffins or ethanol, and with bacteria growing on methanol Inorganic nitrogen is supplied in such processes as ammonia, or as ammon Physlological Carbon Energy Nir。ga source source Autotroph enc Atmos H4 cO Heterotroph As carbon IH3, NH4 (sugars) Heterotroph Carbohydrate As carbon NH3, NH4 sugars, starch culosis As carbon NH3 NH4* (n-paraffins, Bacteria Heterotroph Hydrocarbon As carbon NH3, NH4 (methylotroph) derivatives (methanol Table 4.1 Organisms and substrates in SCP production66 Chapter 4 4.4 Substrates for SCP production For a micrmrganism to grow it must be supplied with all the nutrients required for ceII material and energy production. The physiological types of organism used in SCP production and their corresponding substrates are shown in Table 4.1. Photosynthetic bacteria utilise CQ from the atmosphere and nitrate in inorganic salts or natural ground water media. Algae are similar, growing on nitrate, ammonia or ammonium salt as nitrogen source. Some can also be grown as heterotrophs, in the dark, using sugars as sources of carbon and energy. Heterotrophic bacteria and fin@ for SCP are grown on a variety of organic substrates, serving as both carbon and energy sources. Some organisms have additional requirement for growth factors, such as vitamins. For yeast, the substrate is in the form of sugars, as yeast cells cannot break down polysaccharides, whereas filamentous fungi may in addition be able to use starch (by secreting amylases), pectin (by secreting pectinases) and cellulosic material (by secreting cellulases and hemicellulases). Waste containing cellulosic material is in solid rather than in liquid form. Processes have also been developed with yeasts growing on n-paraffins or ethanol, and with bacteria growing on methanol. Inorganic nitrogen is supplied in such processes as ammonia, or as ammonium salt. pectinases cellulases and hfli&lulmes Organisms Physiological Carbon Energy Nltrogen type source source source Blue-green Autotroph Atmospheric bacteria c02 Algae Fungi Autotroph Atmospheric Heterotroph Carbohydrate Heterotroph Carbohydrate con (sugars) (sugars, starch, pectin, cellulosics) Hydrocarbons and derivatives (n-paraff ins, ethanol) Bacteria Heterotroph Hydrocarbon (methylotroph) derivatives (methanol) Sunlight Sunlight As carbon source As carbon source As carbon source As carbon source N03- NH3, NH4+ N03- NH3, NH4+ N03' NH3, NH4+ NH3, NH4+ NH3, NH4+ Table 4.1 Organisms and substrates in SCP production