Carbon source Carbon source are defined as all the nutrients that can satisfy the need for carbon during the process of microbial growth. It is also called macronutrients(大量营养物) in that it is in the most greatest need only secondary to water. The spectrum of carbon sources(碳源谱) are extremely wide. Heterotrophs and autotrophs The spectrum of carbon sources can be divided into two ty pes organic carbon and inorganic carbon. Those who have to depend on the organic carbon source are heterotrophs, the majority of microorganisms are of this ty pe. And those who use inorganic carbon source as main form are autotrophs. Only a few of microbes are of this typeCarbon source are defined as all the nutrients that can satisfy the need for carbon during the process of microbial growth. It is also called macronutrients(大量营养物) in that it is in the most greatest need only secondary to water. The spectrum of carbon sources (碳源谱)are extremely wide. The spectrum of carbon sources can be divided into two types: organic carbon and inorganic carbon. Those who have to depend on the organic carbon source are heterotrophs, the majority of microorganisms are of this type. And those who use inorganic carbon source as main form are autotrophs. Only a few of microbes are of this type. Carbon source Heterotrophs and autotrophs