Active heterotrophic metabolism is a critical metabolic role performed by sponge-associated microorganisms, but little is known about their capacity to metabolize marine polysaccharides (MPs). Here, we investigated the genome of the sponge-derived Pseudoalteromonas sp. strain PA2MD11 focusing on its macroalgal carbohydrate-degrading potential. Carbohydrate-active enzymes (CAZymes) for the depolymerization of agar and alginate were found in PA2MD11's genome, including glycoside hydrolases (GHs) and polysaccharide lyases (PLs) belonging to families GH16, GH50 and GH117, and PL6 and PL17, respectively. A gene potentially encoding a sulfatase was also identified, which may play a role in the strain's ability to consume carrageenans. The complete metabolism of agar and alginate by PA2MD11 could also be predicted and was consistent with the results obtained in physiological assays. The polysaccharide utilization locus (PUL) potentially involved in the metabolism of agarose contained mobile genetic elements from other marine Gammaproteobacteria and its unusual larger size might be due to gene duplication events. Homology modelling and structural protein analyses of the agarases, alginate lyases and sulfatase depicted clear conservation of catalytic machinery and protein folding together with suitable industrially-relevant features. Pseudoalteromonas sp. PA2MD11 is therefore a source of potential MP-degrading biocatalysts for biorefinery applications and in the preparation of pharmacologically-active oligosaccharides.

主动异养代谢是海绵相关微生物的关键代谢作用，但对其代谢海洋多糖 (MP) 的能力知之甚少。在这里，我们研究了海绵来源的假交替单胞菌的基因组sp. 菌株 PA2MD11 专注于其大型藻类碳水化合物降解潜力。在 PA2MD11 的基因组中发现了用于解聚琼脂和藻酸盐的碳水化合物活性酶 (CAZymes)，包括分别属于家族 GH16、GH50 和 GH117 以及 PL6 和 PL17 的糖苷水解酶 (GHs) 和多糖裂解酶 (PLs)。还鉴定了可能编码硫酸酯酶的基因，该基因可能在该菌株消耗角叉菜胶的能力中起作用。PA2MD11 对琼脂和藻酸盐的完全代谢也可以预测，并且与生理学分析中获得的结果一致。可能参与琼脂糖代谢的多糖利用位点 (PUL) 包含来自其他海洋 Gammaproteobacteria 的可移动遗传元件，其异常大的尺寸可能是由于基因重复事件。琼脂酶、藻酸盐裂解酶和硫酸酯酶的同源性建模和结构蛋白分析描绘了催化机制和蛋白质折叠的明显保守性以及合适的工业相关特征。假交替单胞菌属 因此，PA2MD11 是用于生物精炼应用和制备具有药理活性的寡糖的潜在 MP 降解生物催化剂的来源。