Bacteria can use fatty acids (FAs) from their environment as carbon and energy source. This catabolism is performed by the enzymes of the well-known β-oxidation machinery, producing reducing power and releasing acetyl-CoA that can feed the tricarboxylic acid cycle. FAs are extremely diverse: they can be saturated or (poly)unsaturated and are found in different sizes. The need to degrade such a wide variety of compounds may explain why so many seemingly homologous enzymes are found for each step of the β-oxidation cycle. In addition, the degradation of unsaturated fatty acids requires specific auxiliary enzymes for isomerase and reductase reactions. Furthermore, the β-oxidation cycle can be blocked by dead-end products, which are taken care of by acyl-CoA thioesterases. Yet, the functional characterization of the enzymes required for the degradation of the full diversity of FAs remains to be documented in most bacteria.

细菌可以利用环境中的脂肪酸（FA）作为碳和能源。这种分解代谢是由众所周知的 β-氧化机制的酶进行的，产生还原力并释放乙酰辅酶 A，为三羧酸循环提供能量。FA 极其多样化：它们可以是饱和的或（多）不饱和的，并且有不同的尺寸。降解如此多种化合物的需要可以解释为什么在 β-氧化循环的每个步骤中都发现了如此多看似同源的酶。此外，不饱和脂肪酸的降解需要特定的辅助酶进行异构酶和还原酶反应。此外，β-氧化循环可以被死端产物阻断，而死端产物由酰基辅酶A硫酯酶负责。然而，大多数细菌中降解全部 FA 多样性所需的酶的功能特征仍有待记录。