Heterotrophs refers to an organism that can only use the ready-made organic matter in the external environment as energy and carbon source, ingest these organic matters into the body, convert them into its own constituent substances, and store energy. Heterotrophs can't produce nutrition by itself. It must take other organisms as its source of nutrition and rely on them to survive and reproduce. Including animals and most bacteria and fungi. Is a consumer of organic matter.

Heterotrophic aerobic type: this kind of bacteria is the main member of the bacterial family, with the largest variety and quantity, such as Bacillus subtilis, common pathogenic bacteria and most other bacteria. From the aspect of assimilation, it can be divided into saprophytic and parasitic according to its habitat and the way of obtaining nutrients. There are intermediate types between saprophytic and parasitic, which can be saprophytic or parasitic. For example, the life history of bdellovibrio has two stages: parasitic and saprophytic. From the perspective of alienation, this kind of bacteria is aerobic and must live in an aerobic environment. Molecular oxygen is the final electron acceptor in the process of productivity metabolism, and carries out aerobic respiration. Vibration, stirring or ventilation are needed to provide sufficient oxygen during culture.