Previous studies have focused on the accumulation of lipid and palmitoleic acid in Tribonema spp., while chrysolaminarin produced by these filamentous oleaginous microalgae has rarely been reported. In this study, the effects of different initial nitrogen concentrations on the growth, lipid and chrysolaminarin accumulation of T. utriculosum were investigated, and the extraction route of lipid was also optimized, accompanied by the isolation and characterization of chrysolaminarin. The results showed that the highest biomass concentration (6.21 ± 0.17 g/L) of T. utriculosum was obtained at 3 mM of initial nitrogen concentration with the lowest level of chrysolaminarin (10.74 ± 0.42% of dry weight (DW)), while higher initial nitrogen concentrations were more conducive to lipid and chrysolaminarin accumulation, especially for 18 mM, leading to the highest lipid content (43.80 ± 0.57% of DW). To minimize the biorefinery process cost, an optimized route for lipid extraction was suggested to simultaneously achieve the goal of disintegration of algal structure and extraction of intracellular polysaccharides by dilute acid pretreatment, which improved lipid extraction efficiency from 38.70% to 87.09%. Most importantly, a homogeneous chrysolaminarin was successfully isolated from T. utriculosum and characterized with an average molecular weight of 5.99 kDa. It was found to mainly comprise glucose (60.13%) and was linked by the β-D-(1 → 3) (main chain) and β-D-(1 → 6) (branch chain) glycosidic bonds. This study is the first report on the isolation and characterization of chrysolaminarin from microalgae Tribonema, and provides new insights into fully utilizing T. utriculosum biomass for broadening the potential applications of microalgae-based products.

先前的研究集中在Tribonema spp。中脂质和棕榈油酸的积累，而这些丝状含油微藻产生的chrysolaminarin鲜有报道。本研究研究了不同初始氮浓度对毛霉菌生长，脂质和金桔素积累的影响，并优化了脂质的提取途径，并对其进行了分离和表征。结果表明，棉铃虫的生物量最高（6.21±0.17 g / L）。在3 mM的初始氮浓度下获得了最低的chrysolaminarin含量（干重（DW）的10.74±0.42％），而较高的初始氮浓度更有利于脂质和chrysolaminarin的积累，尤其是18 mM时，导致最高脂质含量（DW的43.80±0.57％）。为了最大程度地减少生物精炼过程的成本，提出了一种优化的脂质提取途径，以同时实现藻类结构的分解和稀酸预处理提取细胞内多糖的目的，从而将脂质提取效率从38.70％提高至87.09％。最重要的是，成功地从毛霉菌中分离出了均一的chrysolaminarin并且具有5.99kDa的平均分子量。发现它主要包含葡萄糖（60.13％），并通过β-D-（1→3）（主链）和β-D-（1→6）（支链）糖苷键连接。这项研究是关于从微藻Tribonema中分离并鉴定出chrysolaminarin的第一份报告，并为充分利用紫锥菊生物质扩大基于微藻的产品的潜在应用提供了新见解。