Requirement for carbon, hydrogen and oxygen Carbon sources: heterotrophs:"CHO autotrophs: CO2 Xtraordinary flexibility No naturally occurring organic molecule cannot be used by some microorganism eg Paraffin( st), rubber Omnivores: use over 100 different carbon compounds Fastidious: catabolize only a few carbon compound Relatively indigestible human-made substances are metabolized by complex populations of microorganismsRequirement for carbon, hydrogen and oxygen Carbon sources: heterotrophs: “CHO” autotrophs: CO2 Extraordinary flexibility: No naturally occurring organic molecule cannot be used by some microorganism. eg. Paraffin（石蜡）, rubber. Omnivores: use over 100 different carbon compounds. Fastidious: catabolize only a few carbon compound Relatively indigestible human-made substances are metabolized by complex populations of microorganisms