Cellulomonas aurantiaca sp. nov., isolated from a soil sample from a tangerine field

Cellulomonas dongxiuzhuiae sp. nov., Cellulomonas wangleii sp. nov. and Cellulomonas fengjieae sp. nov., isolated from the intestinal contents of Marmota himalayana

Six Gram-stain-positive, aerobic or facultative anaerobic, catalase-positive, urease- and oxidase-negative, rod-shaped bacteria (zg-ZUI157T/zg-ZUI40, zg-ZUI222T/zg-ZUI199 and zg-ZUI188T/ zg-ZUI168) were characterized by a polyphasic approach. Optimal growth of the six strains was observed at pH 7.0 and 28 °C. Phylogenetic analyses based on the 16S rRNA gene and 247 core genes revealed that they belong to genus Cellulomonas . The three type strains have low digital DNA-DNA hybridization (19.3–30.1%) and average nucleotide identity values (78.0-85.5%) with all available genomes in the genus Cellulomonas , and a DNA G+C content range of 73.0-74.6 mol%. The major fatty acids detected in strain pairs zg-ZUI157T/zg-ZUI40 and zg-ZUI 222T/zg-ZUI199 were C16:0, anteiso-C15:0 and anteiso A-C15:1, and C16:0, anteiso-C15:0, anteiso A-C15:1 and anteiso-C17:0 in strain pair zg-ZUI188T/zg-ZUI168. Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol mannosides were the major polar lipids detected in the three novel species. MK-9(H4) was the predominant quinone detected in strains zg-ZUI222T (87.4 %) and zg-ZUI188T (91.4 %), and MK-9(H4) (49.1 %) and MK-8 (43.4 %) in strain zg-ZUI157T. The cell-wall sugars detected in the three novel species mainly contained rhamnose. The cell-wall peptidoglycan type of the three novel species was A4β, with an inferred l-Orn–d-Asp interpeptide bridge for strains zg-ZUI157T and zg-ZUI222T, and l-Orn–d-Glu for strain zg-ZUI188T. Based on the results of the phenotypic, phylogenetic, genomic hybridization, average nucleotide identity and chemotaxonomic analyses, the six strains should be classified as belonging to three novel Cellulomonas species, for which the names Cellulomonas dongxiuzhuiae sp. nov. (zg-ZUI157T=GDMCC 1.2559T=KCTC 49678T), Cellulomonas wangleii sp. nov. (zg-ZUI222T=GDMCC 1.2501T=KCTC 49675T) and Cellulomonas fengjieae sp. nov. (zg-ZUI188T=GDMCC 1.2563T=KCTC 49674T) are proposed.

Optimization of bioprocesses with Brewers' spent grain and Cellulomonas uda

Brewers' spent grain (BSG) is a low-value by-product of the brewing process, which is produced in large quantities every year. In this study, the lignocellulosic feedstock (solid BSG) was used to optimize fermentations with Cellulomonas uda. Under aerobic conditions, maximum cellulase activities of 0.98 nkat∙mL-1, maximum xylanase activities of 5.00 nkat∙mL-1 and cell yields of 0.22 gCells∙gBSG -1 were achieved. Under anaerobic conditions, enzyme activities and cell yields were lower, but valuable liquid products (organic acids, ethanol) were produced with a yield of 0.41 gProd∙gBSG -1. The growth phase of the organisms was monitored by measuring extracellular concentrations of two fluorophores pyridoxin (aerobic) and tryptophan (anaerobic) and by cell count. By combining reductive with anaerobic conditions, the ratio of ethanol to acetate was increased from 1.08 to 1.59 molEtOH∙molAc -1. This ratio was further improved to 9.2 molEtOH∙molAc -1 by lowering the pH from 7.4 to 5.0 without decreasing the final ethanol concentration. A fermentation in a bioreactor with 15 w% BSG instead of 5 w% BSG quadrupled the acetate concentration, whilst ethanol was removed by gas stripping. This study provides various ideas for optimizing and monitoring fermentations with solid substrates, which can support feasibility and incorporation into holistic biorefining approaches in the future.

Cellulomonas fulva sp. nov., isolated from oil-contaminated soil

A yellow-coloured, Gram-stain-positive, motile, aerobic and rod-shaped bacteria, designated DKR-3T, was isolated from oil-contaminated experimental soil. Strain DKR-3T could grow at pH 5.0–10.5 (optimum, pH 7.0–8.5), at 10–40 °C (optimum, 25–32 °C) and tolerated 3.5 % of NaCl. Phylogenetic analyses based on its 16S rRNA gene sequence indicated that strain DKR-3T formed a lineage within the family Cellulomonadaceae and was clustered with members of the genus Cellulomonas . Strain DKR-3T had highest 16S rRNA gene sequence similarities to Cellulomonas gelida DSM 20111T (98.3 %), Cellulomonas persica JCM 18111T (98.2 %) and Cellulomonas uda DSM 20107T (97.8 %). The predominant respiratory quinone was tetrahydrogenated menaquinone with nine isoprene units [MK-9(H4)]. The principal cellular fatty acids were anteiso-C15 : 0, C16 : 0 and anteiso-C17 : 0. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The cell-wall diamino acid was l-ornithine whereas rhamnose and glucose were the cell-wall sugars. The DNA G+C content was 74.2mol %. The genome of strain DKR-3T was 3.74 Mb and contained three putative biosynthetic gene clusters. The average nucleotide identity and digital DNA–DNA hybridization relatedness values between strain DKR-3T and its phylogenetically related members were below the species threshold values. Based on a polyphasic study, strain DKR-3T represents a novel species belonging to the genus Cellulomonas , for which the name Cellulomonas fulva sp. nov. is proposed. The type strain is DKR-3T (=KACC 22071T=NBRC 114730T).

Cellulomonas aurantiaca Kim et al. 2020 is a later heterotypic synonym of Cellulomonas algicola Yamamura et al. 2019

Cellulomonas algicola KZ-21^T was compared with Cellulomonas aurantiaca THG-SMD2.3^T to examine the taxonomic relationship between the two type strains. The 16S rRNA gene sequence of Cellulomonas algicola KZ-21^T shared complete similarity (100.0 %) with that of Cellulomonas aurantiaca THG-SMD2.3^T. The results of phylogenetic analyses based on 16S rRNA gene sequences indicated that the two strains formed a tight cluster within the genus Cellulomonas. Genome comparison between the two strains revealed an average nucleotide identity of 99.2 % and a digital DNA-DNA hybridization estimate of 93.7±1.8 %, strongly indicating that the two strains belong to a single species. In addition, neither strain displayed any striking differences in metabolic, physiological or chemotaxonomic features. Therefore, we propose Cellulomonas aurantiaca as a later heterotypic synonym of Cellulomonas algicola.

Cellulomonas shaoxiangyii sp. nov., isolated from faeces of Tibetan antelope (Pantholops hodgsonii) on the Qinghai-Tibet Plateau

Two Gram-stain-positive, catalase-positive and oxidase-negative, aerobic, non-motile, cellobiose-utilizing, short-rod-shaped strains (Z28^T and Z29) were isolated from faeces of Tibetan antelope (Pantholops hodgsonii) collected on the Qinghai-Tibet Plateau. Strain Z28^T shared 98.1, 98.0, 97.8 and 97.4 % 16S rRNA gene similarity, 24.1, 22.8, 23.2 and 26.3 % digital DNA-DNA hybridization relatedness and 80.8, 80.0, 80.7 and 80.9 % average nucleotide identity values with Cellulomonas oligotrophica DSM 24482^T, Cellulomonas flavigena DSM 20109^T, Cellulomonas iranensis DSM 14785^T and Cellulomonas terrae JCM 14899^T, respectively. Results from further phylogenetic analyses based on the 16S rRNA gene and 148 core genes indicated that strains Z28^T and Z29 were closest to C. oligotrophica DSM 24482^T and C. flavigena DSM 20109^T, but clearly separated from the currently recognized species of the genus Cellulomonas. The genomic DNA G+C content of strain Z28^T was 75.3 mol%. The major cellular fatty acids were anteiso-C_15 : 0, anteiso-C_15 : 1 A, C_16 : 0 and anteiso-C_17 : 0. Ribose and mannose were detected as the whole-cell sugars. The major respiratory quinone was MK-9(H₄) and ornithine was the diamino acid of the cell wall. The polar lipids present in strain Z28^T were phosphatidylethanolamine, five phospholipids, two aminophospholipids, aminolipid and three unidentified lipids. Comparison of phenotypic and phylogenetic features between the two strains and the related organisms revealed that Z28^T and Z29 represent a novel species of the genus Cellulomonas, for which the name Cellulomonas shaoxiangyii sp. nov. is proposed. The type strain is Z28^T (=CGMCC 1.16477^T=DSM 106200^T).