发酵透明质酸寡糖兽疫链球菌工程菌株的构建

Construction of engineered Streptococcus zooepidemicus for the production of hyaluronic acid ligosaccharide

摘要:

透明质酸 (HA) 广泛应用于医学、化妆品、食品等领域。HA的生物活性取决于其分子量 (Mw)。透明质酸寡糖由于具有重要的生理活性与特殊生理功能，在医药领域具有重要的应用前景。兽疫链球菌因其发酵周期短、生产强度较强的特点，在商业生产HA上具有广泛的应用。为了高效发酵合成透明质酸寡糖和解决发酵过程的溶氧问题，文中通过在兽疫链球菌WSH-24中过表达透明质酸合酶HasA以及优化表达水蛭来源的透明质酸酶LHAase。重组菌株摇瓶发酵24 h，透明质酸寡糖积累至0.97 g/L，比野生菌提高了182.0%。在3 L发酵罐中发酵24 h，透明质酸寡糖生产强度为294.2 mg/(L·h)，HA积累至7.06 g/L，比野生菌的罐上水平提高了112.4%。文中所构建的发酵合成透明质酸寡糖的兽疫链球菌重组菌株具有重要的应用前景。

关键词:糖胺聚糖，兽疫链球菌，透明质酸寡糖，水蛭透明质酸酶，透明质酸分子量

Abstract:

Hyaluronic acid (HA) is widely used in many fields, such as medicine, cosmetics and food. The bioactivity of HA depends on its molecular weight (Mw). Owing to the important physiological activities and special physiological functions, HA oligosaccharides have important application prospects in medicine fields. Streptococcus zooepidemicus has wide applications in commercial production of HA, due to its short fermentation cycle and strong production intensity. In order to efficiently synthesize HA oligosaccharides and solve the dissolved oxygen in the fermentation process, in this study, we overexpressed HA synthase (HasA) and introduced and optimized the leech hyaluronidase LHAase in Streptococcus zooepidemicus WSH-24. As a result, HA oligosaccharides were efficiently produced with improved dissolved oxygen. After 24 h, HA oligosaccharides production intensity reached to 294.2 mg/(L·h), and the concentration accumulated to 0.97 g/L in flask cultures, which was 1.82 times of the wild strain. Impressively, HA oligosaccharides were increased to 7.06 g/L in 3 L fermentor. The constructed Streptococcus zooepidemicus strain for producing HA oligosaccharides would have broad application prospects.

Key words:glycosaminoglycan, Streptococcus zooepidemicus, hyaluronic acid oligosaccharide, leech hyaluronidase, molecular weight of hyaluronic acid