Tay Nguyen University, Buon Ma Thuot, Daklak 63000, Viet Nam.
Jeonbuk National University, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
Enzyme Microb Technol. 2024 Jan;172:110339. doi: 10.1016/j.enzmictec.2023.110339. Epub 2023 Oct 5.
Agar is a common component biosynthesized from various marine algae species that is widely applied in various fields including food and pharmaceutical industries. However, the structural composition of agar is highly resisted against chemical and biological hydrolysis. Therefore, tremendous research is exploring various pretreatment strategies to break down the intrinsic chemical structural of agar linkage (i.e. neutral agarose and highly sulfated agaropectin) prior for its industrial potential usage. In this research work, a novel agar degrading bacterium was screened and isolated from agriculture soils. Molecular identification using nucleotide sequence of 16 s rRNA region comparison has indicated that the isolate belonged to Priestia genus, and was identified as Priestia megaterium AT7. The maximum enzyme activity was 52.85 ± 1.76 U/mL after 96 h of culture with 5% inoculum size and agitation speed of 180 rpm. Results indicated that the optimal condition for the production of agarose was achieved at pH 7 at 50 °C. The effects of metal ions (e.g. Ca, Co, Cu, Mn, Mg, Zn and Fe) and organic solvents (e.g. acetone, ethanol, methanol, hexane and isopropanol) on enzyme activity were also evaluated. Marine algae hydrolysis evaluation at concentration of 0.1% indicated the enzyme produced reducing sugar of 683.94 ± 26.93 µg/g after 24 h of treatment. It was also found that the highest antioxidant activities obtained after 20 h of treatment was able to achieve 81.76 ± 3.90% at marine algae concentration of 0.1%. The findings obtained from this research work shows the promising application of extracellular agarase to saccharify marine algae for the recovery of value-added bioproducts.
琼胶是一种常见的海洋藻类生物合成成分，广泛应用于食品和制药等各个领域。然而，琼胶的结构组成对化学和生物水解具有很强的抵抗力。因此，大量的研究正在探索各种预处理策略，以打破琼胶键的内在化学结构（即中性琼脂糖和高度硫酸化琼脂果胶），从而实现其工业应用潜力。在这项研究工作中，从农业土壤中筛选和分离出了一种新型的琼脂降解菌。通过 16s rRNA 区域比较的核苷酸序列进行分子鉴定表明，该分离物属于 Prietia 属，被鉴定为 Prietia megaterium AT7。在接种量为 5%、搅拌速度为 180rpm 的条件下培养 96 小时后，酶活达到最大值 52.85±1.76U/mL。结果表明，在 pH7 和 50°C 下，琼脂糖的生产达到最佳条件。还评估了金属离子（如 Ca、Co、Cu、Mn、Mg、Zn 和 Fe）和有机溶剂（如丙酮、乙醇、甲醇、己烷和异丙醇）对酶活性的影响。在 0.1%浓度下对海洋藻类的水解评价表明，该酶在 24 小时处理后产生 683.94±26.93µg/g 的还原糖。还发现，在海洋藻类浓度为 0.1%时，经过 20 小时处理后获得的最高抗氧化活性能够达到 81.76±3.90%。这项研究工作的结果表明，胞外琼胶酶在糖化海洋藻类以回收有价值的生物产品方面具有广阔的应用前景。
