Moguel Ignacio S, Yamakawa Celina K, Pessoa Adalberto, Mussatto Solange I
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark.
Department of Biochemical and Pharmaceutical Technology, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
Front Bioeng Biotechnol. 2020 Dec 17;8:576511. doi: 10.3389/fbioe.2020.576511. eCollection 2020.
L-asparaginase (ASNase) is a therapeutical enzyme used for treatment of acute lymphoblastic leukemia. ASNase products available in the market are produced by bacteria and usually present allergic response and important toxicity effects to the patients. Production of ASNase by yeasts could be an alternative to overcome these problems since yeasts have better compatibility with the human system. Recently, it was found that , a psychrotolerant yeast, produces ASNase. In order to advance the production of ASNase by this yeast, the present study aimed to select suitable process conditions able to maximize the production of this enzyme in a bench-scale bioreactor. Additionally, the accumulation of lipids during the enzyme production process was also determined and quantified. Experiments were carried out with the aim of selecting the most appropriate conditions of initial cell concentration (1.0, 3.5, and 5.6 g L), carbon source (sucrose and glycerol, individually or in mixture) and oxygen transfer rate ( in the range of 1.42-123 h) to be used on the production of ASNase by this yeast. Results revealed that the enzyme production increased when using an initial cell concentration of 5.6 g L, mixture of sucrose and glycerol as carbon source, and of 91.72 h. Under these conditions, the enzyme productivity was maximized, reaching 35.11 U L h, which is already suitable for the development of scale-up studies. Additionally, accumulation of lipids was observed in all the cultivations, corresponding to 2-7 g L (32-40% of the cell dry mass), with oleic acid (C ) being the predominant compound (50.15%). Since the L-asparaginase biopharmaceuticals on the market are highly priced, the co-production of lipids as a secondary high-value product during the ASNase production, as observed in the present study, is an interesting finding that opens up perspectives to increase the economic feasibility of the enzyme production process.
L-天冬酰胺酶（ASNase）是一种用于治疗急性淋巴细胞白血病的治疗性酶。市场上现有的ASNase产品由细菌生产，通常会引起过敏反应，并对患者产生重要的毒性作用。酵母生产ASNase可能是克服这些问题的一种替代方法，因为酵母与人体系统具有更好的兼容性。最近，发现一种耐冷酵母能产生ASNase。为了提高这种酵母生产ASNase的产量，本研究旨在选择合适的工艺条件，以便在实验室规模的生物反应器中使该酶的产量最大化。此外，还对酶生产过程中脂质的积累进行了测定和定量。实验旨在选择最合适的初始细胞浓度（1.0、3.5和5.6 g/L）、碳源（单独或混合使用的蔗糖和甘油）以及氧气传递速率（1.42-123 h范围内），用于这种酵母生产ASNase。结果表明，当使用初始细胞浓度为5.6 g/L、蔗糖和甘油的混合物作为碳源以及氧气传递速率为91.72 h时，酶产量增加。在这些条件下，酶生产率最大化，达到35.11 U/L·h，这已经适合开展放大研究。此外，在所有培养物中均观察到脂质积累，相当于2-7 g/L（占细胞干重的32-40%），其中油酸（C）是主要化合物（50.15%）。由于市场上的L-天冬酰胺酶生物制药价格高昂，本研究中观察到的在ASNase生产过程中作为次要高价值产品联产脂质是一个有趣的发现，为提高酶生产过程的经济可行性开辟了前景。
