Contato Alex Graça, Vici Ana Claudia, Pinheiro Vanessa Elisa, de Oliveira Tássio Brito, Ortolan Guilherme Guimarães, de Freitas Emanuelle Neiverth, Buckeridge Marcos Silveira, Polizeli Maria de Lourdes Teixeira de Moraes
Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Department of Biology, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Folia Microbiol (Praha). 2024 Oct 23. doi: 10.1007/s12223-024-01208-6.
β-Glucans comprise a group of β-D-glucose polysaccharides (glucans) that occur naturally in the cell walls of bacteria, fungi, and cereals. Its degradation is catalyzed by β-glucanases, enzymes that catalyze the breakdown of β-glucan into cello-oligosaccharides and glucose. These enzymes are classified as endo-glucanases, exo-glucanases, and glucosidases according to their mechanism of action, being the lichenases (β-1,3;1,4-glucanases, EC 3.2.1.73) one of them. Hence, we aimed to enhance lichenase production by Thermothelomyces thermophilus through the application of response surface methodology, using tamarind (Tamarindus indica) and jatoba (Hymenaea courbaril) seeds as carbon sources. The crude extract was immobilized, with a focus on improving lichenase activity, using various ionic supports, including MANAE (monoamine-N-aminoethyl), DEAE (diethylaminoethyl)-cellulose, CM (carboxymethyl)-cellulose, and PEI (polyethyleneimine)-agarose. Regarding lichenase, the optimal conditions yielding the highest activity were determined as 1.5% tamarind seeds, cultivation at 50 °C under static conditions for 72 h. Moreover, transitioning from Erlenmeyer flasks to a bioreactor proved pivotal, resulting in a 2.21-fold increase in activity. Biochemical characterization revealed an optimum temperature of 50 °C and pH of 6.5. However, sustained stability at varying pH and temperature levels was challenging, underscoring the necessity of immobilizing lichenase on ionic supports. Notably, CM-cellulose emerged as the most effective immobilization medium, exhibiting an activity of 1.01 U/g of the derivative (enzyme plus support), marking a substantial enhancement. This study marks the first lichenase immobilization on these chemical supports in existing literature.
β-葡聚糖是一类β-D-葡萄糖多糖（葡聚糖），天然存在于细菌、真菌和谷物的细胞壁中。其降解由β-葡聚糖酶催化，β-葡聚糖酶是一类将β-葡聚糖分解为纤维寡糖和葡萄糖的酶。根据作用机制，这些酶可分为内切葡聚糖酶、外切葡聚糖酶和糖苷酶，地衣芽孢杆菌（β-1,3；1,4-葡聚糖酶，EC 3.2.1.73）是其中之一。因此，我们旨在通过应用响应面法，以罗望子（罗望子）和巴西胡桃（孪叶豆）种子作为碳源，提高嗜热栖热菌的地衣芽孢杆菌产量。粗提取物被固定化，重点是使用各种离子载体提高地衣芽孢杆菌活性，包括MANAE（单胺-N-氨乙基）、DEAE（二乙氨基乙基）-纤维素、CM（羧甲基）-纤维素和PEI（聚乙烯亚胺）-琼脂糖。关于地衣芽孢杆菌，确定产生最高活性的最佳条件为1.5%罗望子种子，在50℃静态条件下培养72小时。此外，从锥形瓶过渡到生物反应器被证明是关键的，活性增加了2.21倍。生化特性表明最佳温度为50℃，pH值为6.5。然而，在不同pH和温度水平下保持稳定性具有挑战性，这突出了将地衣芽孢杆菌固定在离子载体上的必要性。值得注意的是，CM-纤维素是最有效的固定化介质，其衍生物（酶加载体）的活性为1.01 U/g，有显著提高。本研究是现有文献中首次将地衣芽孢杆菌固定在这些化学载体上。
