Current applications and different approaches for microbial L-asparaginase production

ABSTRACT L-asparaginase (EC 3.5.1.1) is an enzyme that catalysis mainly the asparagine hydrolysis in L-aspartic acid and ammonium. This enzyme is presented in different organisms, such as microorganisms, vegetal, and some animals, including certain rodent's serum, but not unveiled in humans. It can be used as important chemotherapeutic agent for the treatment of a variety of lymphoproliferative disorders and lymphomas (particularly acute lymphoblastic leukemia (ALL) and Hodgkin's lymphoma), and has been a pivotal agent in chemotherapy protocols from around 30 years. Also, other important application is in food industry, by using the properties of this enzyme to reduce acrylamide levels in commercial fried foods, maintaining their characteristics (color, flavor, texture, security, etc.) Actually, L-asparaginase catalyzes the hydrolysis of L-asparagine, not allowing the reaction of reducing sugars with this aminoacid for the generation of acrylamide. Currently, production of L-asparaginase is mainly based in biotechnological production by using some bacteria. However, industrial production also needs research work aiming to obtain better production yields, as well as novel process by applying different microorganisms to increase the range of applications of the produced enzyme. Within this context, this mini-review presents L-asparaginase applications, production by different microorganisms and some limitations, current investigations, as well as some challenges to be achieved for profitable industrial production.

Current applications and different approaches for microbial L-asparaginase production

L-asparaginase (EC 3.5.1.1) is an enzyme that catalysis mainly the asparagine hydrolysis in L-aspartic acid and ammonium. This enzyme is presented in different organisms, such as microorganisms, vegetal, and some animals, including certain rodent's serum, but not unveiled in humans. It can be used as important chemotherapeutic agent for the treatment of a variety of lymphoproliferative disorders and lymphomas (particularly acute lymphoblastic leukemia (ALL) and Hodgkin's lymphoma), and has been a pivotal agent in chemotherapy protocols from around 30 years. Also, other important application is in food industry, by using the properties of this enzyme to reduce acrylamide levels in commercial fried foods, maintaining their characteristics (color, flavor, texture, security, etc.) Actually, L-asparaginase catalyzes the hydrolysis of L-asparagine, not allowing the reaction of reducing sugars with this aminoacid for the generation of acrylamide. Currently, production of L-asparaginase is mainly based in biotechnological production by using some bacteria. However, industrial production also needs research work aiming to obtain better production yields, as well as novel process by applying different microorganisms to increase the range of applications of the produced enzyme. Within this context, this mini-review presents L-asparaginase applications, production by different microorganisms and some limitations, current investigations, as well as some challenges to be achieved for profitable industrial production.(AU)

Use of PVA-gel immobilized cells: a new strategy for biotechnological production of Xylitol from sugarcane bagasse hidrolysate / Uso de células imobilizadas em gel de PVA: uma nova estratégia para produção biotecnológica de Xilitol a partir de bagaço de cana-de-açúcar

Sugarcane bagasse is one of the most abundant residues in Brazil due to the large number of sugaralcohol industries. This biomass contains a high concentration of carbohydrates, which can be converted into products of high economic value, such as xylitol. Xylitol, a polyol with anticariogenic properties, is similar in sweetening power to sucrose, and has high potential for use in the food and pharmaceutical industries. Several studies have been carried out to produce xylitol by biotechnological processes. However, there is little information on the use of immobilized cells in these bioprocesses. The objective of this review was to present a new possibility to produce xylitol by biotechnological processes, using sugarcane bagasse hydrolysate and immobilized cells in PVA-gel.

O bagaço de cana-de-açúcar é um dos resíduos mais abundantes no Brasil devido ao grande número de indústrias sucroalcooleiras. Esta biomassa contém elevado teor de carboidratos, podendo ser utilizada na produção de compostos de interesse econômico como o xilitol. O xilitol é um poliol de cinco carbonos que apresenta poder adoçante semelhante ao da sacarose e propriedades anti-cariogênicas, tendo elevado potencial de uso nas indústrias alimentícias e farmacêuticas. Diversos estudos buscando o desenvolvimento de processos de produção de xilitol por via biotecnológica têm sido realizados, entretanto pouco tem sido escrito sobre a utilização de células imobilizadas no bioprocesso. A presente revisão tem como objetivo apresentar uma possibilidade de produção de xilitol a partir de hidrolisado hemicelulósico de bagaço de canade-açúcar, em sistema com células imobilizadas em gel de álcool polivinílico.