Fructooligosaccharides (FOSs)—fructose-based oligosaccharides—are typical prebiotics with health-promoting effects in humans and animals. The trisaccharide 1-kestotriose is the most attractive inulin-type FOS. We previously reported a recombinant sucrose:sucrose 1-fructosyltransferase (1-SST, EC 2.4.1.99) from Schedonorus arundinaceus (Sa) that efficiently converts sucrose into 1-kestotriose. In this study, Pichia pastoris PGFT6x-308 constitutively expressing nine copies of the Sa1-SST gene displayed fructosyltransferase activity in undisrupted biomass (49.8 U/ml) and culture supernatant (120.7 U/ml) in fed-batch fermentation (72 hr) with sugarcane molasses. Toluene permeabilization increased 2.3-fold the Sa1-SSTrec activity of whole cells entrapped in calcium-alginate beads. The reaction with refined or raw sugar (600 g/l) yielded 1-kestotriose and 1,1-kestotetraose in a ratio of 8:2 with their sum representing above 55% (wt/wt) of total carbohydrates. The FOSs yield decreased to 45% (wt/wt) when sugarcane syrup and molasses were used as cheaper sucrose sources. The beads retained 80% residual Sa1-SSTrec activity after a 30-day batchwise operation with refined cane sugar at 30°C and pH 5.5. The immobilized biocatalyst is attractive for the continuous production of short-chain FOSs, most particularly 1-kestotriose.

中文翻译：

---

固定化毕赤酵母细胞生产低聚果糖，该细胞表达沙丁鱼蔗糖：蔗糖 1-果糖基转移酶

低聚果糖 (FOS) - 基于果糖的低聚糖 - 是典型的益生元，对人类和动物具有促进健康的作用。三糖 1-酮三糖是最具吸引力的菊粉型 FOS。我们之前报道了一种重组蔗糖：来自 Schedonorus arundinaceus (Sa) 的蔗糖 1-果糖基转移酶 (1-SST, EC 2.4.1.99)，可有效地将蔗糖转化为 1-酮三糖。在这项研究中，组成型表达 9 个 Sa1-SST 基因拷贝的毕赤酵母 PGFT6x-308 在补料分批发酵（72 小时）中未中断的生物质（49.8 U/ml）和培养上清液（120.7 U/ml）中显示出果糖基转移酶活性。甘蔗糖蜜。甲苯透化使包裹在海藻酸钙珠中的全细胞的 Sa1-SSTrec 活性增加了 2.3 倍。与精制糖或粗糖 (600 g/l) 的反应产生比例为 8:2 的 1-酮三糖和 1,1-酮四糖，它们的总和占总碳水化合物的 55% (wt/wt) 以上。当甘蔗糖浆和糖蜜用作更便宜的蔗糖来源时，FOSs 产量下降到 45% (wt/wt)。在 30°C 和 pH 5.5 条件下使用精制蔗糖进行 30 天的分批操作后，珠粒保留了 80% 的残留 Sa1-SSTrec 活性。固定化生物催化剂对于连续生产短链低聚果糖很有吸引力，尤其是 1-酮三糖。在 30°C 和 pH 5.5 条件下使用精制蔗糖进行 30 天的分批操作后，珠粒保留了 80% 的残留 Sa1-SSTrec 活性。固定化生物催化剂对于连续生产短链低聚果糖很有吸引力，尤其是 1-酮三糖。在 30°C 和 pH 5.5 条件下使用精制蔗糖进行 30 天的分批操作后，珠粒保留了 80% 的残留 Sa1-SSTrec 活性。固定化生物催化剂对于连续生产短链低聚果糖很有吸引力，尤其是 1-酮三糖。