Search

BACKGROUND: Microalga‐assisted wastewater treatment systems have gained attention for their efficiency in removing nutrients, chemical oxygen demand, toxic heavy metals and other dissolved compounds, while also producing valuable biomass and demonstrating high CO2 biofixation potential. The current research focuses on investigating the municipal wastewater phycoremediation and heavy metal biosorption ability of three indigenous freshwater microalgal strains: Tetradesmus reginae, Tetradesmus obliquus and Chlorella sorokiniana. RESULTS: The research findings indicate that the microalgal strains T. reginae, T. obliquus and C. sorokiniana exhibited notable performance in biomass accumulation. Specifically, the biomass accumulations were 2.215 ± 0.002, 1.143 ± 0.006 and 0.856 ± 0.021 g L−1, respectively, with initial culture biomasses ranging from 0.5 to 0.6 g L−1. These strains significantly reduced toxic heavy metals (As, 46.86–60.12%; Cd, 52.96–83.18%; Cr, 73.49–82.18%; and Pb, 95.38–96.25%), nutrients (NH4+ & NO3− 100% and PO43− 78–86.41%) as well as chemical oxygen demand (46.02–67.35%), and biosequestered CO2 (0.8–0.18 gCO2 L−1 d−1) during the growth period. Among the strains, T. reginae emerged as the top performer. The Fourier transform infrared spectra of the strain's biomass confirmed the presence of specific functional groups, such as CH, NH, OH and CN, which play a crucial role in ionising and reacting with toxic metal ions and protons in the wastewater. CONCLUSION: This study has shown that the isolated wild microalgal strains have promising phycoremediation and heavy metal adsorption characteristics. Moreover, they exhibit promising rates of CO2 biosequestration. These findings underscore the potential of microalga‐assisted wastewater treatment systems for efficient and eco‐friendly wastewater remediation, as well as biomass generation and CO2 mitigation. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Peribacillus sp. AS_2, a leaf endophytic bacterium isolated from the medicinal plant Alectra sessiliflora, was previously identified using the 16S rRNA gene sequence. The draft genome of AS_2 had a 5,482,853 bp draft circular chromosome, 43 contigs, N50 of 360,633 bp and an average G + C% content of 40.5%. Whole genome sequencing and phenotypic analysis showed that AS_2 was Gram-positive, endospore-forming, motile, and rod-shaped and it showed a high sequence similarity with P. frigoritolerans DSM 8801T. Genomic digital DNA–DNA hybridisation (dDDH) between strain AS_2 and Peribacillus frigoritolerans DSM 8801T and P. castrilensis N3T was 84.8% and 79.2%, respectively, and the average nucleotide identity (ANI) of strain AS_2 with P. frigoritolerans DSM 8801T and P. castrilensis N3T was 97.0% and 96.7%, respectively. The antiSMASH software predicted a total of eight secondary metabolite gene clusters comprising non-ribosomal peptide synthetase (NRPS) type koranimine, terpenes, and siderophore clusters. Strain AS_2 also displayed genes involved in endophytic lifestyle and antibiotic resistance gene clusters such as small multidrug resistance antibiotic efflux pumps (qacJs). Using the multilocus sequence analysis (MLSA), together with the phenotypic data and genomic analysis, we demonstrated that strain AS_2 is a subspecies of P. frigoritolerans DSM 8801T. Genome sequencing of Peribacillus sp. AS_2 from medicinal plants provides valuable genomic information and allows us to further explore its biotechnological applications. [ABSTRACT FROM AUTHOR]

Microalgae are among the few biological resources studied that are found to possess vast biotechnological potential. This study isolated, identified and investigated two wild green microalgal species with substantial potential as a bioresource and climate change mitigation importance. Two isolates, Chlorella sorokiniana and Tetradesmus reginae were cultivated in selected artificial media under laboratory conditions. The isolates were analysed for nutrient consumption, biomass productivity, CO2 biosequestration rate, elemental composition and fatty acid methyl profiles/composition. The outcome showed maximum daily biomass productivity of 0.128 ± 0.003 and 0.2 ± 0.004 g L−1 for C. sorokiniana and T. reginae, respectively. CO2 biosequestration rate of T. reginae was the highest among the isolates, indicating that it can act as a biological climate change mitigation agent. Moreover, T. reginae recorded a significantly higher (p < 0.05) total lipid and carbohydrate content than C. sorokiniana. The C/N ratio for T. reginae was significantly higher than the C/N ratio for C. sorokiniana. Tetradesmus reginae also demonstrated the ability to produce a considerable quantity of omega-3 oils; hence, the species is of nutraceutical importance. Furthermore, T. reginae demonstrated maximal carbohydrate content and is therefore considered a potential feedstock for bioethanol production. Chlorella sorokiniana, on the other hand, showed a remarkable (p < 0.05) protein content making it a potential source for human food and animal feed supplement. Finally, the two isolates met both European and American quality biodiesel standards with exceptional cetane (CN) and iodine numbers (IV). [ABSTRACT FROM AUTHOR]

This article, titled "Editorial: Plant growth-promoting and associated microbes: multi-, meta-omics, and applications," discusses the use of multiomics and metaomics techniques to study the functions of endophytes in plant growth and development. It highlights the potential applications of endophytes in various sectors, such as agriculture, medicine, and drug discovery. The article includes research on the role of halotolerant bacterial endophytes in mitigating salinity stress, the production of secondary metabolites by bacterial and fungal endophytes with potential applications in plant growth and protection as well as the treatment of HIV and multidrug-resistant fungi, and the role of the Beauveria bassiana endophyte in enhancing plant growth and resistance to pathogens. The article emphasizes the importance of understanding plant-endophyte interactions for developing sustainable agricultural practices and harnessing the potential of plant-associated microbiota to enhance crop productivity. [Extracted from the article]

Pseudarthrobacter phenanthrenivorans strain MHSD1 is a bacterial endophyte isolated from sterilized leaves of Pellaea calomelanos, a medicinal plant capable of growing in arid environments. Here, we report the draft genome sequence and annotation of this bacterial endophyte. The draft genome sequence of P. phenanthrenivorans strain MHSD1 has 4 450 468 bp with a G + C content of 65.30%. The National Center for Biotechnology Information Prokaryotic Genome Annotation Pipeline identified a total of 4004 protein-coding genes, 56 genes coding for RNAs, and 82 pseudogenes. Biosynthesis pathways for various phytohormones such as auxin, salicylic acid, ethylene, cytokinin, jasmonic acid, abscisic acid, and gibberellins were identified. Putative genes involved in various characteristics of bacterial endophyte lifestyle such as transport, motility, adhesion, membrane proteins, secretion and delivery systems, plant cell wall modification, and detoxification were identified. Phylogenomic analysis showed P. phenanthrenivorans strain MHSD1 to be a subspecies of P. phenanthrenivorans Sphe3. [ABSTRACT FROM AUTHOR]

In the present study, eleven endophytic bacterial strains, Herbaspirillum sp. (GP-SGM1, GP-SGM2, GP-SGM3, and GP-SGM11), Pseudomonas sp. (GP-SGM4, GP-SGM5), Novosphingobium sp. GP-SGM6, Chryseobacterium sp. GP-SGM7, Labedella sp. GP-SGM8, Brevibacterium sp. GP-SGM9, and Pseudomonas sp. GP-SGM10, were isolated from the rhizomes of Gunnera perpensa L. The growth kinetics, assessed through maximum growth rates (μmax) and optical density (OD) values, revealed that GP-SGM7 exhibited highest μmax values of 0.33 ± 0.01 hours (h)-1 with an OD of 4.20 ± 0.04. In contrast, GP-SGM11 exhibited the lowest μmax of 0.12 ± 0.05 h-1 and the smallest OD of 1.50 ± 0.00. In addition, the endophyte crude extracts were tested for antibacterial activity against five pathogenic strains using the disk diffusion method, with GP-SGM7 crude extracts exhibiting promising antibacterial activity against Klebsiella pneumoniae and Staphylococcus aureus. Antioxidant activity was determined by DPPH (2, 2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays. The crude extracts of GP-SGM1, GP-SGM7, GP-SGM9, and GP-SGM10 were the most effective at scavenging DPPH radicals, with GP-SGM7 also exhibiting a high FRAP value of 0.54 ± 0.01. These findings emphasize the therapeutic potential of endophytic bacteria from G. perpensa L. in addressing skin-related issues, including bacterial infections and free radicals., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

A Gram-stain-positive, endospore-forming endophytic bacterial strain designated MHSD28 T was isolated from surface-sterilized leaves of Dicoma anomala collected from Eisleben, Botlokwa, Limpopo Province, South Africa. The phenotypic and phylogenetic characteristics of strain MHSD28 T were consistent with those of members within the Bacillus cereus group. Comparative analysis between this strain and its relatives confirmed that it belongs to this group and forms a monophyletic branch. The digital DNA-DNA hybridization values between strain MHSD28 T and its relatives were lower than the 70 % threshold for species delineation. To further determine its phylogenetic position, multi-locus sequence analysis (MLSA) based on five concatenated housekeeping gene ( gyrB , atpD , DnaK , rpoB and rpoD ) sequences, phenotypic analysis, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) biotyper identification, fatty acid and polar lipid profile analyses were carried out. Phenotypic characterization, MLSA, whole genome sequence based analyses and MALDI-TOF results placed strain MHSD28 T within the B. cereus group. The major fatty acids were iso-C 15 : 0 and summed feature 3 and the main polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The respiratory quinone was menaquinone-7. The cell-wall peptidoglycan structure included meso -diaminopimelic acid. Considering the above results, strain MHSD28 T represents a novel species of the B. cereus group, for which the name Bacillus dicomae sp. nov. is proposed. The type strain is MHSD28 T (=BD 2262 T =LMG 32287 T =CECT 30671 T ).