Abstract：
OBJECTIVE: Fed-batch cultures have rarely been used in single cell protein (SCP) research. This work evaluated multiple yeast species for suitability as SCP cultivated using glucose- and sucrose-based substrate and performed in-depth studies of fed-batch SCP cultivation kinetics for selected yeasts, including determination of specific crude nitrogen-to-protein conversion factors.
METHODS: SCP was cultivated using fully synthetic media in flask batch or bioreactor fed-batch cultures. Crude nitrogen and nucleic acid content were determined using the Dumas method and fluorescence assay kits, respectively.
RESULTS: C. utilis compared favorably to other yeasts in flask batch cultures in terms of process yield (0.52 ± 0.01 gx gs-1) and crude nitrogen content (10.0 ± 0.5 and 9.9 ± 0.5%CDW for glucose and sucrose, respectively). This is the first time biomass composition data was reported for SCP cultivated in fed-batch mode. C. utilis crude nitrogen content was consistent across the tested conditions (protein content stabilized around 50%CDW in fed-batch), while that of the benchmark yeast S. cerevisiae was higher in batch cultures and at the beginning of fed-batch relative to the end (protein content decreased over time and stabilized around 43%CDW). Total nucleic acid content of the yeasts was similar (6.8%CDW and 6.3%CDW, for C. utilis and S. cerevisiae, respectively), with crude nitrogen-to-protein conversion factors of 4.97 and 5.80.
CONCLUSIONS: This study demonstrated the suitability of C. utilis as SCP, notably the robustness of its crude nitrogen content (as an indicator of protein content) across batch and fed-batch conditions, compared to that of the benchmark yeast S. cerevisiae.
METHODS: SCP was cultivated using fully synthetic media in flask batch or bioreactor fed-batch cultures. Crude nitrogen and nucleic acid content were determined using the Dumas method and fluorescence assay kits, respectively.
RESULTS: C. utilis compared favorably to other yeasts in flask batch cultures in terms of process yield (0.52 ± 0.01 gx gs-1) and crude nitrogen content (10.0 ± 0.5 and 9.9 ± 0.5%CDW for glucose and sucrose, respectively). This is the first time biomass composition data was reported for SCP cultivated in fed-batch mode. C. utilis crude nitrogen content was consistent across the tested conditions (protein content stabilized around 50%CDW in fed-batch), while that of the benchmark yeast S. cerevisiae was higher in batch cultures and at the beginning of fed-batch relative to the end (protein content decreased over time and stabilized around 43%CDW). Total nucleic acid content of the yeasts was similar (6.8%CDW and 6.3%CDW, for C. utilis and S. cerevisiae, respectively), with crude nitrogen-to-protein conversion factors of 4.97 and 5.80.
CONCLUSIONS: This study demonstrated the suitability of C. utilis as SCP, notably the robustness of its crude nitrogen content (as an indicator of protein content) across batch and fed-batch conditions, compared to that of the benchmark yeast S. cerevisiae.
摘要：
目的：补料分批培养很少用于单细胞蛋白（SCP）研究。这项工作评估了多种酵母物种作为使用葡萄糖和蔗糖基底物培养的SCP的适用性，并对选定酵母的补料分批SCP培养动力学进行了深入研究。包括确定特定的粗氮至蛋白质转换因子。
方法：使用全合成培养基在烧瓶分批或生物反应器补料分批培养中培养SCP。使用Dumas方法和荧光测定试剂盒测定粗氮和核酸含量,分别。
结果：C.在工艺产量（0.52±0.01gxgs-1）和粗氮含量（葡萄糖和蔗糖的CDW为10.0±0.5和9.9±0.5％，分别)。这是首次报道以补料分批模式培养的SCP的生物量组成数据。C.utilis粗氮含量在测试条件下是一致的（补料分批中蛋白质含量稳定在50％CDW左右），而基准酵母酿酒酵母在分批培养中和补料分批开始时相对于结束时较高(蛋白质含量随时间下降，并稳定在43%左右的CDW)。酵母的总核酸含量相似(6.8%CDW和6.3%CDW,对于产产酵母和酿酒酵母，分别)，粗氮到蛋白质的转化率分别为4.97和5.80。
结论：这项研究证明了C.utilis作为SCP的适用性，特别是在分批和补料分批条件下，其粗氮含量（作为蛋白质含量的指标）的稳健性，与基准酵母酿酒酵母相比。
方法：使用全合成培养基在烧瓶分批或生物反应器补料分批培养中培养SCP。使用Dumas方法和荧光测定试剂盒测定粗氮和核酸含量,分别。
结果：C.在工艺产量（0.52±0.01gxgs-1）和粗氮含量（葡萄糖和蔗糖的CDW为10.0±0.5和9.9±0.5％，分别)。这是首次报道以补料分批模式培养的SCP的生物量组成数据。C.utilis粗氮含量在测试条件下是一致的（补料分批中蛋白质含量稳定在50％CDW左右），而基准酵母酿酒酵母在分批培养中和补料分批开始时相对于结束时较高(蛋白质含量随时间下降，并稳定在43%左右的CDW)。酵母的总核酸含量相似(6.8%CDW和6.3%CDW,对于产产酵母和酿酒酵母，分别)，粗氮到蛋白质的转化率分别为4.97和5.80。
结论：这项研究证明了C.utilis作为SCP的适用性，特别是在分批和补料分批条件下，其粗氮含量（作为蛋白质含量的指标）的稳健性，与基准酵母酿酒酵母相比。
