Genome sequencing of cold-adapted Planococcus bacterium isolated from traditional shrimp paste and protease identification.

BACKGROUND: Psychrophiles have evolved to adapt to freezing environments, and cold-adapted enzymes from these organisms can maintain high catalytic activity at low temperature. The use of cold-adapted enzymes has great potential for the revolution of food and molecular biology industries. RESULTS: In this study, four different strains producing protease were isolated from traditional fermented shrimp paste, one of which, named Planococcus maritimus XJ11 by 16S rRNA nucleotide sequence analysis, exhibited the largest protein hydrolysis clear zone surrounding the colonies. Meanwhile, the strain P. maritimus XJ11 was selected for further investigation because of its great adaptation to low temperature, low salinity and alkaline environment. The enzyme activity assay of P. maritimus XJ11 indicated that the optimum conditions for catalytic activity were pH 10.0 and 40 °C. Moreover, the enzyme also showed an increasing activity with temperatures from 10 to 40 °C and retained more than 67% activity of the maximum over a broad range of salinity (50-150 g L-1 ). Genome sequencing analysis revealed that strain XJ11 possessed one circular chromosome of 3 282 604 bp and one circular plasmid of 67 339 bp, with a total number of 3293 open reading frames (ORFs). Besides, 21 genes encoding protease, including three serine proteases, were identified through the NR database. CONCLUSION: Cold-adapted bacterium P. maritimus XJ11 was capable of producing alkaline proteases with high catalytic efficiency at low or moderate temperatures. Furthermore, the favorable psychrophilic and enzymatic characters of strain P. maritimus XJ11 seem to have a promising potential for industrial application. © 2020 Society of Chemical Industry.

A Sustainable Approach for the Green Synthesis of Silver Nanoparticles from Solibacillus isronensis sp. and Their Application in Biofilm Inhibition.

The use of bacteria as nanofactories for the green synthesis of nanoparticles is considered a sustainable approach, owing to the stability, biocompatibility, high yields and facile synthesis of nanoparticles. The green synthesis provides the coating or capping of biomolecules on nanoparticles surface, which confer their biological activity. In this study, we report green synthesis of silver nanoparticles (AgNPs) by an environmental isolate; named as AgNPs1, which showed 100% 16S rRNA sequence similarity with Solibacillus isronensis. UV/visible analysis (UV/Vis), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized nanoparticles. The stable nature of nanoparticles was studied by thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS). Further, these nanoparticles were tested for biofilm inhibition against Escherichia coli and Pseudomonas aeruginosa. The AgNPs showed minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.12 µg/mL and 6.25 µg/mL for E. coli, and 1.56 µg/mL and 3.12 µg/mL for P. aeruginosa, respectively.

Exploring the Pharmacological Potentials of Biosurfactant Derived from Planococcus maritimus SAMP MCC 3013.

Therapeutic potential of biosurfactant (BS) has been improved in recent years. Our present study deals with production of BS from Planococcus maritimus SAMP MCC 3013 in a mineral salt medium (MSM) supplemented with glucose (1.5% w/v). Further, BS has been purified and partially characterized as glycolipid type through our previous publication. Current research article aimed to evaluate biological potential of BS against Mycobacterium tuberculosis, Plasmodium falciparum and cancerous cell lines. Planococcus derived glycolipid BS was found to be a promising inhibitor of M. tuberculosis (MTB) H37Ra at IC50 64.11 ± 1.64 µg/mL and MIC at 160.8 ± 1.64 µg/mL. BS also showed growth inhibition of P. falciparum at EC50 34.56 ± 0.26 µM. Additionally, BS also displayed the cytotoxicity against HeLa (IC50 41.41 ± 4.21 µg/mL), MCF-7 (IC50 42.79 ± 6.07 µg/mL) and HCT (IC50 31.233 ± 5.08 µg/mL) cell lines. Molecular docking analysis was carried for the most popular glycolipid type BS namely Rhamnolipid (RHL) aiming to interpret the possible binding interaction for anti-tubercular and anti-cancer activity. This analysis revealed the involvement of RHL binding with enoyl reductase (InhA) of M. tuberculosis. Docking studies of RHL with tubulin directed several hydrophobic and Vander Waal interactions to exhibit anti-cancer potential. The present study will be helpful for further development of marine bioactive molecules for therapeutic applications. Their anti-tubercular, anti-plasmodial and cytotoxic activities make BS molecules as a noteworthy candidate to combat several diseases. To the best of our knowledge, this is the first report on projecting the pharmacological potential of Planococcus derived BS.

Improvements in the growth performance, immunity, disease resistance, and gut microbiota by the probiotic Rummeliibacillus stabekisii in Nile tilapia (Oreochromis niloticus).

The application of probiotics as an eco-friendly alternative to antibiotics is an emerging strategy for sustainable aquaculture. In the present study, Rummeliibacillus stabekisii was isolated from the gut of Nile tilapia, and the effects of R. stabekisii on the growth, innate immunity, disease resistance, and gut microbiota of Nile tilapia (Oreochromis niloticus) were investigated. The results showed significantly increased weight gain (WG), feed conversion ratio (FCR), and feed efficiency (FE) in Nile tilapia fed R. stabekisii for 8 weeks compared to those in fish fed a control diet. Intestinal digestive enzymes such as protease, cellulase, and xylanase were also significantly increased in the R. stabekisii-administered groups. Enhanced cumulative survival was exhibited in fish fed R. stabekisii after challenge with Aeromonas hydrophila and Streptococcus iniae. Immune parameters such as the phagocytic activity, respiratory bursts, and superoxide dismutase of head kidney leukocytes; serum lysozyme activity; and expression of the cytokine genes interleukin-1ß, tumor necrosis factor-α, transforming growth factor-ß, and heat shock protein 70 were significantly elevated in fish fed R. stabekisii. Administration of R. stabekisii considerably increased the abundance of potential probiotics (Bacillus and Lactobacillus spp.) and reduced abundances of potential pathogenic bacteria (Streptococcus and Staphylococcus spp.) in fish intestines. The present study indicated that dietary supplementation with R. stabekisii improved the growth, immunity, disease resistance, and gut microflora of Nile tilapia. This research is the first study reporting that the genus Rummeliibacillus is a potential probiotic in animals, suggesting that R. stabekisii can be used as a feed additive to enhance the growth and health status in tilapia.

Combining chemical flocculation and bacterial co-culture of Cupriavidus taiwanensis and Ureibacillus thermosphaericus to detoxify a hardwood hemicelluloses hydrolysate and enable acetone-butanol-ethanol fermentation leading to butanol.

Butanol, a fuel with better characteristics than ethanol, can be produced via acetone-butanol-ethanol (ABE) fermentation using lignocellulosic biomass as a carbon source. However, many inhibitors present in the hydrolysate limit the yield of the fermentation process. In this work, a detoxification technology combining flocculation and biodetoxification within a bacterial co-culture composed of Ureibacillus thermosphaericus and Cupriavidus taiwanensis is presented for the first time. Co-culture-based strategies to detoxify filtered and unfiltered hydrolysates have been investigated. The best results of detoxification were obtained for a two-step approach combining flocculation to biodetoxification. This sequential process led to a final phenolic compounds concentration of 1.4 g/L, a value close to the minimum inhibitory level observed for flocculated hydrolysate (1.1 g/L). The generated hydrolysate was then fermented with Clostridium acetobutylicum ATCC 824 for 120 h. A final butanol production of 8 g/L was obtained, although the detoxified hydrolysate was diluted to reach 0.3 g/L of phenolics to ensure noninhibitory conditions. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2753, 2019.

Simplistic approach in extracellular synthesis of silver nanoparticles via bioreducing potential of Planococcus plakortidis strain BGCC-51 isolated from dye industry effluent soil.

Here, extracellular synthesis of silver nanoparticles (AgNPs) was carried out by Planococcus plakortidis strain BGCC-51 isolated from dye industry effluent soil. The microbes were isolated, screened, and characterised by molecular analysis (accession number KX776160). The optimisation of synthesis of AgNPs to determine the optimum substrate level (1-5 mM), pH (5-9), and temperature (25-55°C) were further carried out. P. plakortidis strain BGCC-51 gave best yield of AgNPs at substrate concentration 5 mM, pH 8, and at 35°C. Synthesised AgNPs were characterised by scanning electron microscope and high-resolution transmission electron microscope. The size of synthesised AgNPs was in the range of 20-40 nm having spherical morphology. The AgNPs were found to show antimicrobial activity against bacteria such as Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Staphylococcus aureus (ATCC 29213).

Structure-Based Engineering of an Artificially Generated NADP+-Dependent d-Amino Acid Dehydrogenase.

A stable NADP+-dependent d-amino acid dehydrogenase (DAADH) was recently created from Ureibacillus thermosphaericusmeso-diaminopimelate dehydrogenase through site-directed mutagenesis. To produce a novel DAADH mutant with different substrate specificity, the crystal structure of apo-DAADH was determined at a resolution of 1.78 Å, and the amino acid residues responsible for the substrate specificity were evaluated using additional site-directed mutagenesis. By introducing a single D94A mutation, the enzyme's substrate specificity was dramatically altered; the mutant utilized d-phenylalanine as the most preferable substrate for oxidative deamination and had a specific activity of 5.33 µmol/min/mg at 50°C, which was 54-fold higher than that of the parent DAADH. In addition, the specific activities of the mutant toward d-leucine, d-norleucine, d-methionine, d-isoleucine, and d-tryptophan were much higher (6 to 25 times) than those of the parent enzyme. For reductive amination, the D94A mutant exhibited extremely high specific activity with phenylpyruvate (16.1 µmol/min/mg at 50°C). The structures of the D94A-Y224F double mutant in complex with NADP+ and in complex with both NADPH and 2-keto-6-aminocapronic acid (lysine oxo-analogue) were then determined at resolutions of 1.59 Å and 1.74 Å, respectively. The phenylpyruvate-binding model suggests that the D94A mutation prevents the substrate phenyl group from sterically clashing with the side chain of Asp94. A structural comparison suggests that both the enlarged substrate-binding pocket and enhanced hydrophobicity of the pocket are mainly responsible for the high reactivity of the D94A mutant toward the hydrophobic d-amino acids with bulky side chains.IMPORTANCE In recent years, the potential uses for d-amino acids as source materials for the industrial production of medicines, seasonings, and agrochemicals have been growing. To date, several methods have been used for the production of d-amino acids, but all include tedious steps. The use of NAD(P)+-dependent d-amino acid dehydrogenase (DAADH) makes single-step production of d-amino acids from oxo-acid analogs and ammonia possible. We recently succeeded in creating a stable DAADH and demonstrated that it is applicable for one-step synthesis of d-amino acids, such as d-leucine and d-isoleucine. As the next step, the creation of an enzyme exhibiting different substrate specificity and higher catalytic efficiency is a key to the further development of d-amino acid production. In this study, we succeeded in creating a novel mutant exhibiting extremely high catalytic activity for phenylpyruvate amination. Structural insight into the mutant will be useful for further improvement of DAADHs.

Modulation of phytoremediation and plant growth by the treatment with PGPR, Ag nanoparticle and untreated municipal wastewater.

The present attempt was made to determine the effects of untreated municipal wastewater (MW) on growth and physiology of maize and to evaluate the role of Ag nanoparticle and plant-growth-promoting rhizobacteria (PGPR) when interacting with MW used for irrigation. It was used for the isolation of PGPR. The isolates were identified and characterized based on the colony morphology, C/N source utilization pattern using miniaturized identification system (QTS 24), catalase (CAT) and oxidase tests, and 16S rRNA sequence analyses. The three PGPR isolates were Planomicrobium chinense (accession no. NR042259), Bacillus cereus (accession no. CP003187) and Pseudomonas fluorescens (accession no. GU198110). The isolates solubilized phosphate and exhibited antibacterial activities against pathogenic bacteria i.e., Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Klebsiella pneumoniae and Escherichia coli and antifungal activities against Helminthosporium sativum and Fusarium solani. The untreated MW irrigation as well as Ag nanoparticle treatment resulted in significant accumulation of Ni in the rhizosphere soil. PGPR induced accumulation of Ni and Pb in the rhizosphere soil and maize shoot. Ag nanoparticle also caused Ni and Pb accumulation in maize shoot. Combined treatment with PGPR, Ag nanoparticle and MW resulted in decreased accumulation of Pb and Ni both in the rhizosphere soil and maize shoot. Combined treatment of Ag nanoparticle, MW and PGPR decreased Na accumulation and increased K accumulation. Ag nanoparticle increased Fe and Co accumulation but decreased Zn and Cu accumulation in MW treatment; in combined treatment, it reduced PGPR-induced accumulation of Co and Fe in the rhizosphere and Co accumulation in shoot. PGPR significantly increased root weight, shoot weight, root length, shoot length, leaf area, and proline, chlorophyll and carotenoid content of the maize plant. Ag nanoparticle also enhanced the leaf area, fresh weight, root length and antioxidant activities of maize. Treatment with Ag nanoparticle increased the gibberellic acid (GA) and abscisic acid (ABA) content of maize leaves but decreased the accumulation of GA in the presence of PGPR and MW.