β-1, 3-Xylanase is one of the most important hydrolytic enzymes to prepare oligosaccharides as functional foods in seaweed industry. However, less than five β-1, 3-xylanases have been experimentally expressed and characterized; moreover, none of them is psychrophilic and salt tolerant. Here, we mined a novel β-1, 3-xylanase (Xyl512) from the genome of the deep-sea bacterium Flammeovirga pacifica strain WPAGA1 and biochemically characterized it in detail. The Xyl512 did not contain any carbohydrate-binding module; the catalytic domain of it belonged to the glycoside hydrolase family 26. The optimum temperature and pH of the purified β-1, 3-xylanase was 20 °C and pH 7.0 in the condition of no NaCl. However, they shifted to 30 °C and 7.5 with 1.5 mol/L NaCl, respectively. In this condition (1.5 mol/L NaCl), the overall activity was 2-fold as high as that without NaCl. Based on the residue interactions and the electrostatic surfaces, we addressed the possible mechanism of its adaption to low temperature and relative high NaCl concentration. The Xyl512 showed significantly reduced numbers of hydrogen bonds leading to a more flexible structure, which is likely to be responsible for its cold adaptation. While the negatively charged surface may contribute to its salt tolerance. The β-1, 3-xylanase we identified here was the first reported psychrophilic and halophilic one with functionally characterized. It could make new contributions to exploring and studying the β-1, 3-xylanase for further associated investigations.

β-1，3-木聚糖酶是将寡糖制备为海藻工业中功能性食品的最重要的水解酶之一。然而，通过实验表达和表征的β-1,3-木聚糖酶少于五个。此外，它们都不是耐温和耐盐的。在这里，我们从深海细菌Flammeovirga pacifica的基因组中提取了一种新型的β-1，3-木聚糖酶（Xyl512）菌株WPAGA1，并对其生化特性进行了详细描述。Xyl512不包含任何碳水化合物结合模块。它的催化结构域属于糖苷水解酶家族26。在没有NaCl的条件下，纯化的β-1、3-木聚糖酶的最佳温度和pH值为20°C，pH值为7.0。但是，它们分别用1.5 mol / L NaCl转变为30°C和7.5。在此条件下（1.5 mol / L NaCl），总活性是没有NaCl时的2倍。基于残留物的相互作用和静电表面，我们研究了其适应低温和较高NaCl浓度的可能机理。Xyl512的氢键数量明显减少，从而导致结构更加灵活，这可能是其冷适应性的原因。带负电荷的表面可能有助于其耐盐性。我们在这里鉴定出的β-1、3-木聚糖酶是第一个报道的具有功能性的嗜冷和嗜盐酶。它可能为探索和研究β-1，3-木聚糖酶的进一步研究做出新的贡献。