Cellulosimicrobium composti sp. nov., a thermophilic bacterium isolated from compost

Cellulamides: A New Family of Marine-Sourced Linear Peptides from the Underexplored Cellulosimicrobium Genus

Bioprospecting the secondary metabolism of underexplored Actinomycetota taxa is a prolific route to uncover novel chemistry. In this work, we report the isolation, structure elucidation, and bioactivity screening of cellulamides A and B (1 and 2), two novel linear peptides obtained from the culture of the macroalga-associated Cellulosimicrobium funkei CT-R177. The host of this microorganism, the Chlorophyta Codium tomentosum, was collected in the northern Portuguese coast and, in the scope of a bioprospecting study focused on its associated actinobacterial community, strain CT-R177 was isolated, taxonomically identified, and screened for the production of antimicrobial and anticancer compounds. Dereplication of a crude extract of this strain using LC-HRMS(/MS) analysis unveiled a putative novel natural product, cellulamide A (1), that was isolated following mass spectrometry-guided fractionation. An additional analog, cellulamide B (2) was obtained during the chromatographic process and chemically characterized. The chemical structures of the novel linear peptides, including their absolute configurations, were elucidated using a combination of HRMS, 1D/2D NMR spectroscopy, and Marfey's analysis. Cellulamide A (1) was subjected to a set of bioactivity screenings, but no significant biological activity was observed. The cellulamides represent the first family of natural products reported from the Actinomycetota genus Cellulosimicrobium, showcasing not only the potential of less-explored taxa but also of host-associated marine strains for novel chemistry discovery.

Trends in the development and current perspective of thermostable bacterial hemicellulases with their industrial endeavors: A review

Hemicellulases are enzymes that hydrolyze hemicelluloses, common polysaccharides in nature. Thermophilic hemicellulases, derived from microbial strains, are extensively studied as natural biofuel sources due to the complex structure of hemicelluloses. Recent research aims to elucidate the catalytic principles, mechanisms and specificity of hemicellulases through investigations into their high-temperature stability and structural features, which have applications in biotechnology and industry. This review article targets to serve as a comprehensive resource, highlighting the significant progress in the field and emphasizing the vital role of thermophilic hemicellulases in eco-friendly catalysis. The primary goal is to improve the reliability of hemicellulase enzymes obtained from thermophilic bacterial strains. Additionally, with their ability to break down lignocellulosic materials, hemicellulases hold immense potential for biofuel production. Despite their potential, the commercial viability is hindered by their high enzyme costs, necessitating the development of efficient bioprocesses involving waste pretreatment with microbial consortia to overcome this challenge.

Streptomyces sennicomposti sp. nov., an actinomycete isolated from compost of Senna siamea (Lam.)

A member of the genus Streptomyces , designated RCPT1-4T, was isolated from compost of Senna siamea (Lam.), collected from an agricultural area in Rayong province, Thailand. The spore morphology and the presence of ll-diaminopimelic acid in the peptidoglycan indicate that RCPT1-4T shows the typical properties of members of the genus Streptomyces . On the basis of the results of 16S rRNA gene sequence analysis, the strain should be classified as representing a member of the genus Streptomyces and was most closely related to Streptomyces fumigatiscleroticus NBRC 12999T with the highest 16S rRNA gene sequence similarity of 99.2 %, followed by Streptomyces spiralis NBRC 14215T (99.0 %). In addition, RCPT1-4T shared the highest average nucleotide identity by blast (ANIb) (86.0 %), and digital DNA–DNA hybridization (dDDH) (32.1 %) values with S. spiralis NBRC 14215T. Furthermore, several physiological and biochemical differences were observed between RCPT1-4T and the closely related type strains of species with validly published names. These taxonomic data indicated that RCPT1-4T could be considered to represent a novel species of the genus Streptomyces and the name Streptomyces sennicomposti sp. nov. is proposed for this strain. The type strain is RCPT1-4T (=TBRC 11260T=NBRC 114303T).

Cellulosimicrobium protaetiae sp. nov., isolated from the gut of the larva of Protaetia brevitarsis seulensis

A Gram-stain-positive, non-spore-forming, yellow-pigmented, non-motile, non-flagellated, facultative anaerobic and rod-shaped bacterial strain, designated BI34T, was isolated from the gut of the larva of Protaetia brevitarsis seulensis. Strain BI34T grew at 15–40 °C (optimum, 37 °C), at pH 6.5–9.0 (optimum, pH 7.5) and in the presence of 0–7 % (w/v) NaCl (optimum, 2 %). Based on the results of 16S rRNA gene sequence analysis, strain BI34T belonged to the phylum Actinobacteria and was closely related to Cellulosimicrobium funkei NBRC 104118T (99.3 %), Cellulosimicrobium cellulans NBRC 15516T (99.1 %), Cellulosimicrobium composti BIT-GX5T (99.0 %), Cellulosimicrobium fucosivorans SE3T (99.0 %), Cellulosimicrobium marinum NBRC 110994T (98.4 %) and Cellulosimicrobium terreum DS-61T (97.0 %). The genome to genome relatedness of the average nucleotide identity (ANI) and the digital DNA–DNA hybridization (dDDH) values calculated by the Genome-to-Genome Distance Calculator between strain BI34T and its related species mentioned above were lower than the threshold of 95 and 70 % for speciation, respectively. The predominant menaquinone of strain BI34T contained MK-9(H4), and the major fatty acids were anteiso-C15 : 0, C16 : 0 and anteiso-C17 : 0. Strain BI34T had diphosphatidylglycerol and phosphatidylglycerol as major polar lipids. The whole-cell sugars were galactose, glucose and ribose, and the cell-wall peptidoglycan contained lysine, alanine, aspartic acid and glutamic acid. The DNA G+C content of strain BI34T was 73.8 mol%. The difference in physiological and biochemical characteristics and the below-threshold values of genome-to-genome relatedness indicate that strain BI34T represents a novel species in the genus Cellulosimicrobium , for which the name Cellulosimicrobium protaetiae sp. nov. is proposed. The type strain is BI34T (=KCTC 49302T=NBRC 114073T).