Aromatic compound degradation: characterizing the benzoate oxidation (BOX) pathway in Burkholderia xenovorans LB400

芳香化合物约占地球生物量的25%，是仅次于碳水化合物的第二大天然产物。由于芳香环的固有稳定性，这些化合物的自然衰减非常慢。然而，许多细菌已经进化出生物降解能力，可以利用各种芳香化合物作为能源。这些能力的发展是由于环境中许多芳香族化合物以回收植物材料的形式广泛存在。然而，人造芳香族污染物对细菌降解构成了重大挑战。这些化合物不仅在化学上更加复杂，而且它们只在相对较短的时间内接触到微生物降解物。因此，这些外来化合物，其中许多是从原油中提取的，持续存在于环境中，对生物圈造成不可逆转的破坏。刺激这些污染物从环境中去除的最有效的策略是操纵细菌的代谢途径，以增加蛋白质的稳定性和拓宽底物的专一性。作为对这些生物系统进行基本工程的先决条件，对所涉及的酶的详细描述是必不可少的。为此，本研究计划的目标是确定芳香族化合物在异种芽孢杆菌LB400中通过新的苯甲酸氧化(BOX)途径降解的机制。这项研究的长期目标是设计更有效的策略来加速环境有毒芳香族污染物的生物修复。

Aromatic compounds compose approximately 25% of the Earth's biomass and are the second most abundant class of natural products next to carbohydrates. Due to the inherent stability of the aromatic ring, natural attenuation of these compounds is very slow. Many bacteria, however, have evolved biodegradative capabilities that can make use of a wide variety of aromatic compounds as sources of energy. These capabilities have evolved due to widespread availability of many aromatic compounds in the environment in the form of recycled plant material. Man-made aromatic pollutants, however, pose major challenges for bacterial degradation. Not only are these compounds more chemically complex, but they have only been exposed to microbial degraders for a relatively short period of time. As a result, these xenobiotic compounds, many of which are derived from crude oil, persist in the environment and cause irreversible damage to the biosphere. The most effective strategy to stimulate the removal of these contaminants from the environment is to manipulate the metabolic pathways of bacteria to increase protein stability and broaden substrate specificity. As a prerequisite step to the rationale engineering of these biological systems, detailed descriptions of the enzymes involved are essential. To this end, the goal of this research program is to define the mechanism by which aromatic compounds are degraded via the novel benzoate oxidation (box) pathways in B. xenovorans LB400. The long-term goal of this research is to design more efficient strategies for the accelerated bioremediation of environmentally toxic aromatic based pollutants.