A proteomic, reverse-genetic and sequencing approach to reveal genes and enzymes for LAS-surfactant degradation in bacterial communities

工业化学品的完全生物降解会给环境微生物群落带来巨大的挑战。一个突出的例子是外生洗衣液表面活性剂LAS（线性烷基苯磺酸盐；第4-磺胺基烷烃）的矿化。商用LAS是一种复杂的异构体混合物，它的矿化是由两层异养细菌群落（LAS-community）完成的：第一层的细菌利用LAS-烷基链生长，并将LAS转化为短链SPCs（磺苯羧酸酯）；第二层的细菌使这些spc矿化。迄今为止，完整的LAS和SPC途径以及所涉及的基因和酶，以及LAS群落的系统发育组成（例如在污水处理厂）仍然未知。现在，一个由三个成员组成的基因组测序的“模型as群落”是可用的，Parvibaculum lavamentivorans DS-1（第一级），Comamonas testosterone - KF-1和Delftia acid - ovorans SPH-1（第二级）。这允许通过蛋白质组学和反向遗传方法重新理解LAS和spc降解。该探索有望深入了解这些重要的新型降解途径的进化，并且，例如，发现新的P450单加氧酶和baeyer - villiger型单加氧酶。然而，“模型LAS-community”只矿化了商业LAS生成的许多spc的一个子集。因此，需要催化商业LAS的完全降解的环境界预计要复杂得多，但这从未得到证明。因此，我们还将通过大规模平行测序方法，首先探索LAS-和spc -降解关键基因的丰富度和多样性，以了解其系统发育的复杂性。

The complete biodegradation of industrial chemicals can impose great challenges to environmental microbial communities. One prominent example is the mineralization of xenobiotic laundry surfactant LAS (linear alkylbenzene sulfonate; sec. 4-sulfophenyl alkane). Commercial LAS is a complex mixture of isomers, and its mineralization is accomplished by heterotrophic bacterial communities (LAS-community) in two tiers: bacteria in the first tier utilize the LAS-alkyl chains for growth and convert LAS to short-chain SPCs (sulfophenyl carboxylates); bacteria in the second tier mineralize these SPCs. To date, the complete LAS and SPC pathways and the genes and enzymes involved remain unknown, as well as the phylogenetic composition of the LAS-community, e.g. in sewage treatment plants. Now, a three-member, genome-sequenced ‘model LAS-community’ is available, Parvibaculum lavamentivorans DS-1 (first tier) with Comamonas testosteroni KF-1 and Delftia acidovorans SPH-1 (second tier). This allows for renewed attack on understanding LAS- and SPC-degradation, through a proteomic and reverse-genetic approach. The exploration is expected to deliver insight into the evolution of these important, novel degradation pathways, and, e.g., discover novel P450 monooxygenases and Baeyer-Villiger-type monooxygenases. However, the ‘model LAS-community’ mineralizes only a subset of the many SPCs generated from commercial LAS. Hence, the environmental community needed to catalyze the complete degradation of commercial LAS is expected to be much more complex, but this has never been demonstrated. Therefore, also the environmental LAS-community will be explored, firstly, for its phylogenetic complexity, and secondly, for the abundance and diversity of key genes for LAS- and SPC-degradation, through a massively-parallel sequencing approach.