Jul 2026· Journal of the College of Basic Education· 0 citations
Abstract
Soil-occupy Brevibacillus parabrevius PS12 species are known for their metabolically versatile and it is being discovered as source of natural enzymes valuable to industry. Arginase catalyzes the processing of L-arginine to L-ornithine and urea, it is the one that plays a significant role in nitrogen metabolism Finding novel bacterial strains from environmental sources that are capable of producing the arginase enzyme is crucial for expanding microbial resources for industrial and pharmaceutical use. Among the 20 isolates, one isolate was identified as Brevibacillus parabrevis PS12 (97% 16S rRNA similarity, GenBank accession no. (PX118439.1), representing the first report from Iraqi soil. Arginase activity reached 8.3 U/mg protein a peak in nutritional source with maltose as a arbone source and casein as a Nitrogen source, the physical parameters also effect on enzyme specific activity at 7.0 pH, 37°C, and 48 hours of incubation time with shaker incubator 150 rpm to ensure the homogeneity of all medium components and continuous aeration all these factors contributed to an increase in bacterial biomass which led to a rise in the specific activity of arginase.
L-Asparaginase is an important enzyme with therapeutic applications. Current commercial enzymes from E. coli and Erwinia chrysanthemi have limitations, such as high glutaminase activity, creating a need for more stable alternatives. This study aimed to isolate and optimize the production of L-Asparaginase from native, halotolerant Bacillus subtilis strains (DAR and D6A) isolated from central Iran, to find an alternative source for this therapeutically important enzyme. The enzyme was initially isolated using polyethylene glycol (PEG) precipitation. Key factors affecting enzyme production were screened using the Plackett-Burman design and subsequently optimized via the Box-Behnken response surface methodology. PEG precipitation at concentrations of 15-20% for PEG 4000/6000 and 10-15% for PEG 8000/10000 was most effective for initial enzyme separation, yielding specific activities of 4.8 U/mg and 5.2 U/mg for strains DAR and D6A, respectively. Optimization revealed that the most influential factors for maximum L-Asparaginase production were 17.6 g/L NaCl, 4.99 g/L KH2PO4, and 10 g/L asparagine for strain DAR, and 1.49 g/L glucose, 10 g/L NaCl, and 9.98 g/L asparagine for strain D6A. The isolated halotolerant B. subtilis strains are capable of producing L-Asparaginase. PEG precipitation is a suitable method for initial purification, and statistical optimization successfully identified the critical culture conditions to enhance enzyme yield significantly. These strains represent promising sources for the production of this clinically valuable enzyme.
K. Hosseini, Parvin Akbarzadehlaleh, S. Hallaj-Nezhadi et al.· Preparative Biochemistry & B...· 0 citations
The development of robust enzyme systems and the use of low-cost feedstocks for lignocellulosic biomass deconstruction remain major challenges for biorefineries. Here, we report a strategy to discover and produce thermostable hemicellulolytic enzymes from industrial microbiomes enriched on spent mushroom substrate (SMS) at 70 °C. A thermophilic bacterium representing a putative novel species, Parageobacillus sp. DSM 35475, was isolated and cultivated on a medium composed exclusively of SMS and digestate, demonstrating the feasibility of producing extracellular enzymes from agro-industrial residues. The resulting cell-free secretome exhibited xylanase activity of 0.22 U/mL, with an optimum at 80 °C and pH 7, while retaining more than 30% of its maximal activity between 60 and 90 °C and more than 50% activity after prolonged incubation at 75-80 °C. More than 40% of the initial activity was preserved after 80 days of storage at 4 °C. HPAEC-PAD analysis of hydrolysis products, together with zymographic and genomic analyses, indicated the presence of a multifunctional hemicellulolytic system comprising endo-xylanase, β-xylosidase, α-L-arabinofuranosidase, and endo-mannanase activities. The secretome hydrolysed beechwood xylan, arabinoxylan and alkali-pretreated SMS, releasing mixtures of mono- and oligosaccharides under thermophilic conditions. Genome annotation predicted a diverse CAZyme repertoire and a dedicated xylan/arabinan utilisation locus consistent with the observed biochemical phenotype. Overall, this study demonstrates the feasibility of producing a thermostable hemicellulolytic secretome from low-cost agro-industrial residues and identifies Parageobacillus sp. DSM 35475 as a promising source of thermophilic enzymes for future lignocellulose bioconversion.
Luca Bombardi, Valerio Sabellico, Luca Zuliani et al.· International Journal of Bio...· 0 citations
Endophytic bacteria associated with medicinal plants represent a potential source of microorganisms with useful enzymatic and antagonistic properties. In this study, 14 bacterial isolates were recovered from the leaves, roots, flowers, and petioles of Inula helenium and screened for morphological, biochemical, and hydrolytic characteristics. Isolate IH-B3, which showed the most pronounced starch- and casein-hydrolysis zones during preliminary screening, was selected for further characterization. MALDI-TOF mass spectrometry assigned the isolate to Bacillus subtilis with an identification score of 2.26, and the strain was designated B. subtilis UzMU25. Its 1444 bp 16S rRNA gene sequence was deposited in GenBank under accession number PZ593820. The strain was catalase- and lecithinase-positive but gelatinase- and hemolysis-negative, and it grew at pH 6.5 and in the presence of horse bile under the qualitative assay conditions used. Hydrolysis-zone diameters ranged from 46 to 52 mm for amylase, 34 to 42 mm for protease, and 10 to 16 mm for lipase activity. In direct antagonism assays, UzMU25 inhibited all six bacterial and fungal test organisms, producing inhibition zones of 26–36 mm. Biofilm biomass varied with incubation time and reached its highest corrected OD590 value at 12 h (0.780 ± 0.025). Antibiotic-disc testing showed a 10 mm inhibition zone for vancomycin, indicating reduced susceptibility under the applied conditions and requiring further investigation of its genetic basis and potential transferability. No mortality was observed during the preliminary acute oral study following administration of the tested preparation at doses up to 10,000 mg kg−1, and no visible dermal or conjunctival irritation was detected. Overall, UzMU25 exhibited preliminary enzymatic, antagonistic, and biofilm-forming characteristics of biotechnological interest. However, whole-genome antimicrobial-resistance screening and more comprehensive phenotypic and toxicological evaluations are required before the strain can be recommended for probiotic or other practical applications.
Luiza Tagayeva, K. Normurodova, S. Jabborov et al.· Microorganisms· 0 citations
Underground biomethanation represents a promising solution for green energy storage. An isolate of Methanothermobacter thermautotrophicus was obtained in previous study from an underground gas reservoir where it played a key role in a successful in-situ biomethanation experiment. In this study, the physiological and environmental tolerances of the strain are characterised. Optimal methane evolution rates were observed at 55-65 °C and pH 6.5-7.0, methane production was significantly increased by agitation (up to 2.29 mmol CH4·h-1·L-1). The strain showed higher tolerance to NH4Cl (up to 0.6 M) than to NaCl (optimal 0.04-0.4 M). The strain was also tested for its resistance to silver nanoparticles. The whole-genome sequence of the strain was determined, and the corrosion potential was evaluated. To visualise the cells, Scanning Electron Microscopy (SEM) and a method of Advanced Environmental Scanning Electron Microscopy (A-ESEM) were used. These findings describe the behaviour of M.thermautotrophicus under suboptimal conditions and highlight the need for further optimization to improve methane production yields.
N. Hanišáková, Anna Štaud, Eva Kotrlová et al.· Bioresource Technology· 0 citations
Bacterioruberin is a C50 carotenoid gaining more interest because of its important biological properties. This study aimed to the identification and characterization of a bacterial strain producing this attracting carotenoid, Arthrobacter sp. strain CP30. Phylogenetic analysis based on 16S rRNA gene sequences and whole genome comparison showed that strain CP30 belongs to the Arthrobacter agilis group with Arthrobacter bussei being the closest relative. Sequence similarity of the 16S rRNA gene of CP30 to described Arthrobacter species as well as average nucleotide identity values indicate that CP30 represents a new species within the genus Arthrobacter. The strain has been cultivated under controlled fermentation parameters, and the obtained biomass was investigated for carotenoids and lipids quali-quantitative profiles characterization. The biomass extracts enriched in bacterioruberin have been evaluated for antimicrobial and antioxidant properties. The bacterioruberin produced by the strain reached up a carotenoid titer of 1.28 mg L-1 in 72 h, with a yield of 327.67 ± 6.6 μg g-1 of dry biomass, a productivity of 0.02 mg/L/h, and showed an IC50 value of 3.87 μg/mL. The most abundant fatty acids were 12-methyltetradecanoic, 14-methylpentadecanoic and 13-methyltetradecanoic. Whereas, among the intact lipids, glycolipids, phospholipids, diacylglycerols, and triacylglycerols have been identified in the investigated strain. This study allowed pointing out the potential of strain CP30 as a promising bacterioruberin producer, representing an interesting natural carotenoids source to be further investigated as suitable candidate for feed and food application. Comparison of key protein sequences involved in bacterioruberin biosynthesis of CP30 and A. bussei showed sequence similarities of >90%.
Francesca Rigano, Alessia Tropea, G. Micalizzi et al.· Food microbiology· 0 citations
A strictly anaerobic bacterial strain, F2T, was isolated from an anaerobic bioreactor fermenting source-separated organic waste. Cells of strain F2T are non-spore-forming, rod-shaped (1.5–2.5 × 0.27–0.33 µm), and Gram-negative, although they possess a monoderm cell wall architecture. The strain grew at 37 °C within a pH range of 5 to 8 and produced short-, branched-, and medium-chain carboxylates as well as ammonium, H2 and CO2, with acetate and propanoate produced or consumed depending on fermentation conditions. The genome consists of a single 2.4 Mbp chromosome with a G+C content of 50.2% and 2,131 predicted genes. Phylogenetic analysis of the 16S rRNA gene against other isolates revealed that strain F2T is most similar to Eubacterium pyruvativorans I-6T (92.06% 16S rRNA identity). Based on further phenotypic, genomic, and phylogenetic analysis, strain F2T represents a novel genus and species within the family Anaerovoracaceae with the proposed name Peptonella octanoica gen. nov. sp. nov. The type strain is F2T (strain accession pending). As a member of this same genus-level clade, we propose reclassifying Eubacterium pyruvativorans as Peptonella pyruvativorans comb. nov. These findings disambiguate Peptonella spp. from the phylogenetically distant and phenotypically distinct Eubacterium limosum ATCC 8486T.
Dinesh Kumar Nallasamy, B. Lindner, Christopher E. Lawson· bioRxiv· 0 citations