Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok 10150, Thailand.
Systems Biology and Bioinformatics Laboratory, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok 10150, Thailand.
Int J Syst Evol Microbiol. 2022 Aug;72(8). doi: 10.1099/ijsem.0.005494.
Oil palm empty fruit bunch (OPEFB) is lignocellulosic waste from the palm oil industry in Southeast Asia. It is difficult to degrade because of its complex matrix and recalcitrant structure. To decompose OPEFB, highly efficient micro-organisms and robust enzymatic systems are required. A bacterium with high degradation ability against untreated OPEFB was isolated from earthworm soil biofertilizer and designated as strain EW123. Cells were Gram-stain-positive, rod-shaped and catalase-positive. In tests, the strain was negative for mycelium formation, motility, nitrate reductase and urease. The 16S rRNA gene analysis of the isolate showed 98.21 % similarity to NBRC 3747, whereas similarity to other species was below 98 %. The genome of strain EW123 was 3 834 009 bp long, with 73.97 mol% G+C content. Polar lipid analysis of strain EW123 indicated phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol and aminophospholipid as the lipid components of the cell wall. The major cellular fatty acid was anteiso-C (41.26 %) and the isomer of 2,6-diaminopimelic acid (DAP) was -DAP. The average nucleotide identity value between the genome sequences of EW123 and NBRC 3747 was 88.6 %. In addition, the digital DNA-DNA hybridization and genome average amino acid between those strains were 36.1 and 89.68 %, respectively. The ORF number (186) of carbohydrate-active enzymes, including cellulases, xylanases, mannanase, lipase and lignin-degrading enzymes, was higher than those of related strains. These results indicate that the polyphasic characteristics of EW123 differ from those of other related species in the genus . We therefore propose a novel species of the genus , namely sp. nov. (type strain TBRC 11805=NBRC 114552), with the ability to effectively degrade untreated OPEFB.
油棕空果串（OPEFB）是东南亚棕榈油工业的木质纤维素废物。由于其复杂的基质和顽固的结构，很难降解。要分解 OPEFB，需要高效的微生物和强大的酶系统。从蚯蚓土壤生物肥料中分离出一株对未处理的 OPEFB 具有高降解能力的细菌，并命名为菌株 EW123。细胞革兰氏阳性，杆状，过氧化氢酶阳性。在试验中，该菌株菌丝体形成、运动性、硝酸盐还原酶和脲酶均为阴性。分离株的 16S rRNA 基因分析显示与 NBRC 3747 的相似度为 98.21%，而与其他物种的相似度低于 98%。菌株 EW123 的基因组长 3834009bp，G+C 含量为 73.97mol%。菌株 EW123 的极性脂分析表明，细胞壁的脂类成分有磷脂酰甘油、磷脂酰乙醇胺、双磷脂酰甘油和氨基磷脂。主要细胞脂肪酸为 anteiso-C（41.26%），2,6-二氨基庚二酸（DAP）的异构体为-DAP。EW123 与 NBRC 3747 基因组序列之间的平均核苷酸同一性值为 88.6%。此外，两株菌的 DNA-DNA 杂交数字和基因组平均氨基酸分别为 36.1%和 89.68%。碳水化合物活性酶（包括纤维素酶、木聚糖酶、甘露聚糖酶、脂肪酶和木质素降解酶）的 ORF 数量（186）高于相关菌株。这些结果表明，EW123 的多相特征与属内其他相关种不同。因此，我们提出了一个新的属，即 sp. nov.（模式菌株 TBRC 11805=NBRC 114552），具有有效降解未处理的 OPEFB 的能力。
