L-asparaginase Production by Leucosporidium scottii in a Bench-Scale Bioreactor With Co-production of Lipids

Abstract

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 Leucosporidium scottii, 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–1), carbon source (sucrose and glycerol, individually or in mixture) and oxygen transfer rate (kLa in the range of 1.42–123 h–1) 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–1, mixture of sucrose and glycerol as carbon source, and kLa of 91.72 h–1. Under these conditions, the enzyme productivity was maximized, reaching 35.11 U L–1 h–1, 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–1 (32–40% of the cell dry mass), with oleic acid (C18:1) 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.

Cis-Element Engineering Promotes the Expression of Bacillus subtilis Type I L-Asparaginase and Its Application in Food

“…L-asparaginase (EC 3.5.1.1) is a member of the amidohydrolase family that catalyzes the conversion of L-asparagine to L-aspartic acid and ammonia, and the molecular reaction scheme is shown in Figure 1 [ 1 ]. Because tumor cells lack the enzyme asparagine synthetase ability, the enzyme has received more attention for its efficiency in inhibiting tumor cell proliferation by depriving them of nutrition (L-asparagine), resulting in tumor cells starving to death, with little effect on healthy cells due to their enzyme asparagine synthetase ability [ 2 ]. The enzyme was also employed as a promising acrylamide-mitigating agent to manufacture acrylamide-free food products by eliminating asparagine (a significant precursor of acrylamide), with no modification in appearance, sensory qualities, flavor, and nutrition [ 3 , 4 , 5 , 6 ], in addition to its clinical application.…”

Molecular Analysis of L-Asparaginases for Clarification of the Mechanism of Action and Optimization of Pharmacological Functions

“…Of interest are enzymes from the bacteria Leucosporidium scottii , Anoxybacillus flavithermus , extremophile yeast, Bacillus antitudinis , etc., living in high- and low-temperature and highly saline environments [ 80 , 149 , 150 , 151 ]. Recently L-ASNase from Melioribacter roseus , which belongs to the Ignavibacteriae Bacteroidetes/Chlorobi group, was purified and characterized.…”

Biodiversidad microbiana en la producción del biofármaco L-asparaginasa: Una revisión sobre su potencial terapéutico

“…Su cercanía evolutiva con los humanos, principalmente en términos de modificaciones postraduccionales permite esperar que las enzimas posean menor probabilidad de producir hipersensibilidad ( 11,12,31 ). En ese sentido, las levaduras despiertan gran interés debido a su mejor compatibilidad y estabilidad en el suero, además de poseer un pH óptimo cercano al fisiológico ( 7,32,33 ). Por lo tanto, las enzimas destacan notablemente como potenciales biofármacos gracias a sus características bioquímicas (menor probabilidad de reacciones adversas y diferentes niveles de actividad de L-glutaminasa) ( 4, 9 ).…”