Bacillus lehensis—an alkali-tolerant bacterium isolated from cassava starch wastewater: optimization of parameters for cyclodextrin glycosyltransferase production

Fabrication of TPGS decorated Etravirine loaded lipidic nanocarriers as a neoteric oral bioavailability enhancer for lymphatic targeting

Etravirine (ERVN) is a potential NNRTI (non-nucleoside reverse transcriptase inhibitor) in treating HIV infection. It possesses extremely low oral bioavailability. The present research aims to optimize the formulation and characterization of TPGS-enriched ERVN-loaded lipid-based nanocarriers (NLCs) for HIV-infected patients. The formulation, ERVN-TPGS-NLCs, was optimized by central composite rotational design using a modified-solvent emulsification process. Various characterization parameters of NLCs were evaluated, including globule size of 121.56 ± 2.174 nm, PDI of 0.172 ± 0.042, the zeta potential of - 7.32 ± 0.021 mV, %EE of 94.42 ± 8.65% of ERVN and %DL was 8.94 ± 0.759% of ERVN and spherical shape was revealed by TEM. PXRD was also performed to identify the crystallinity of the sample. In-vitro drug release showed % a cumulative drug release of 83.72 ± 8.35% at pH 1.2 and 90.61 ± 9.11% at pH 6.8, respectively, whereas the % cumulative drug release from drug suspension (ERVN-S) was found to be 21.13 ± 2.01% at pH 1.2 and 24.84 ± 2.51 at pH 6.8 at the end of 48 h. Further, the intestinal permeation study and confocal microscope showed approximately three-fold and  two-fold increased permeation in ERVN-TPGS-NLCs and ERVN-NLCs across the gut sac compared to ERVN-S. Hemolysis compatibility and lipolysis studies were performed to predict the in-vivo fate of the formulation. The pharmacokinetic study revealed a 3.13-fold increment in the relative bioavailability, which agrees with the ex-vivo studies, and lymphatic uptake was validated by using cycloheximide along with designed formulation, which showed the impact of lymphatic uptake in AUC. This study ensures that ERVN-TPGS-NLCs take lymphatic uptake to minimize the first-pass metabolism followed by improved oral bioavailability of ERVN. Thus, the enhanced bioavailability of ERVN can reduce the high dose of ERVN to minimize the adverse effects related to dose-related burden.

Gamma cyclodextrin glycosyltransferase from evansella caseinilytica: production, characterization and product specificity

Alkalohalophilic Evansella caseinilytica produced an extracellular cyclodextrin glycosyltransferase (CGTase) with cyclization activity of 43.5 ± 4.4 U/L in M1 medium containing 1% starch and 6% NaCl in nutrient broth at 37 ºC, pH 9.0, after 48 h. This is the first report of CGTase from this bacterium. 0.1% starch was found to induce CGTase, and further optimization using one variable at a time approach followed by statistical optimization led to 5.5-fold enhancement resulting in 240.5 ± 5.46 U/L. Six parameters were identified as positive signals using Plackett-Burman (PB). Of these, yeast extract, MgSO4 and tryptone were taken further for Response Surface Methodology (RSM) by disposing beef extract and fixing starch and soya peptone. The optimized M4 medium consisted of tryptone (0.1%, w/v), yeast extract (0.25%, w/v), MgSO4 (8 mM, w/v), potato starch (0.1%, w/v) and soya peptone (0.2%, w/v). CGTase was further purified with 6.44-fold purification and 19.32% yield employing starch affinity. It was found to be monomeric, corresponding to a size of 68 kDa as estimated by SDS-PAGE and was further confirmed to be 65 kDa by size exclusion chromatography. γ-Cyclodextrins were produced as the major product with a conversion of 5% soluble starch into 20.38% γ-cyclodextrins after 24 h reaction, as determined by HPLC. Peptide fingerprint after LC-MS analysis matched with IPT/TIG domain-containing protein within the genome of E. caseinilytica. Further blastp analysis revealed the closest homology with γ-CGTase from an alkalophilic E. clarkii, thereby confirming CGTase from E. caseinilytica as γ-CGTase.

Lipid nanocarrier of selegiline augmented anti-Parkinson's effect via P-gp modulation using quercetin

In the present study, SEL was loaded in a lipid nanocarrier (LNC) formulation with a P-gp pump inhibitor i.e., Quercetin (QUR) for improving the bioavailability of the SEL in the brain via the oral route. SEL-QUR LNC was formulated using modified emulsiosonication method and optimized using central composite rotatable design (CCRD) design. The results showed that optimized SEL-QUR LNC formulation was spherical with globule size, polydispersity index, entrapment efficiency and zeta potential within the range of 92.46-95.34 nm, 0.239-0.248, 88.94-91.26%, and -6.21 to -7.75 mV respectively. A 4-fold and 6-fold increase was observed in the permeation of SEL from SEL-QUR LNC across the gut sac in comparison with SEL-QUR and SEL suspensions respectively. CLSM images showed 2-fold deeper permeation of SEL across intestinal membrane demonstrating excellent in vivo prospect of the formulation. The behavioural studies including forced swimming, muscle coordination, locomotor activity, akinesia, and catalepsy were performed in the haloperidol-induced PD rats that demonstrated increased efficacy of the formulation in contrast to the SEL-QUR and SEL suspensions. These studies concluded that developed LNC formulation loaded SEL with P-gp inhibitor had the potential in improving bioavailability of SEL in the brain via oral route.

Genomic insights into the phylogeny of Bacillus strains and elucidation of their secondary metabolic potential

The genus Bacillus constitutes a plethora of species that have medical, environmental, and industrial applications. While genus Bacillus has been the focus of several studies where genomic data have been used to resolve many taxonomic issues, there still exist several ambiguities. Through the use of in-silico genome-based methods, we tried to resolve the taxonomic anomalies of a large set of Bacillus genomes (n = 178). We also proposed species names for uncharacterized strains and reported genome sequence of a novel isolate Bacillus sp. RL. In the hierarchical clustering on genome-to-genome distances, we observed 11 distinct monophyletic clusters and investigated the functional pathways annotated as the property of these clusters and core-gene content of the entire dataset. Thus, we were able to assert the possible outlier strains (n = 17) for this genus. Analyses of secondary metabolite potential of each strain helped us unravel still unexplored diversity for various biosynthetic genes.

Active-electrode biosensor of SnO2 nanowire for cyclodextrin detection from microbial enzyme

Cyclodextrin (CD) is a conical compound used in food and pharmaceutical industry to complexation of hydrophobic substances. It is a product of microbial enzymes which converts starch into CD during their activity. We aim to detect CD using active-electrode biosensor of SnO₂. They were grown on active electrode by the VLS method. The CD consists of several glucose units which have hydroxyl groups which tend to bind to interface states present in nanowires changing their conductivity. Experimental results of electrical conductivity at different CD concentrations are presented. A model that describes the influence of adsorbed glucose on nanowires and its electrical properties is also presented. Some general observations are performed on the applicability of the CD adsorption method by the nanowire-based biosensor.

Deep Hypersaline Anoxic Basins as Untapped Reservoir of Polyextremophilic Prokaryotes of Biotechnological Interest

Deep-sea hypersaline anoxic basins (DHABs) are considered to be among the most extreme ecosystems on our planet, allowing only the life of polyextremophilic organisms. DHABs’ prokaryotes exhibit extraordinary metabolic capabilities, representing a hot topic for microbiologists and biotechnologists. These are a source of enzymes and new secondary metabolites with valuable applications in different biotechnological fields. Here, we review the current knowledge on prokaryotic diversity in DHABs, highlighting the biotechnological applications of identified taxa and isolated species. The discovery of new species and molecules from these ecosystems is expanding our understanding of life limits and is expected to have a strong impact on biotechnological applications.

Draft Genome Sequence of Bacillus lehensis M136, Isolated from the Manleluag Hyperalkaline Spring in Pangasinan, Philippines

Here, we report the draft whole-genome sequence of Bacillus lehensis M136, isolated from a hyperalkaline spring located in Pangasinan, Philippines. From 24 scaffolds, the total genome assembly length is 3,985,437 bp.

Here, we report the draft whole-genome sequence of Bacillus lehensis M136, isolated from a hyperalkaline spring located in Pangasinan, Philippines. From 24 scaffolds, the total genome assembly length is 3,985,437 bp. Industrially important genes like cyclodextrin glycosyltransferase (CGTase) and proteases were detected in this draft genome.

A comparative genomic analysis of the alkalitolerant soil bacterium Bacillus lehensis G1

Bacillus lehensis G1 is a Gram-positive, moderately alkalitolerant bacterium isolated from soil samples. B. lehensis produces cyclodextrin glucanotransferase (CGTase), an enzyme that has enabled the extensive use of cyclodextrin in foodstuffs, chemicals, and pharmaceuticals. The genome sequence of B. lehensis G1 consists of a single circular 3.99 Mb chromosome containing 4017 protein-coding sequences (CDSs), of which 2818 (70.15%) have assigned biological roles, 936 (23.30%) have conserved domains with unknown functions, and 263 (6.55%) have no match with any protein database. Bacillus clausii KSM-K16 was established as the closest relative to B. lehensis G1 based on gene content similarity and 16S rRNA phylogenetic analysis. A total of 2820 proteins from B. lehensis G1 were found to have orthologues in B. clausii, including sodium-proton antiporters, transport proteins, and proteins involved in ATP synthesis. A comparative analysis of these proteins and those in B. clausii and other alkaliphilic Bacillus species was carried out to investigate their contributions towards the alkalitolerance of the microorganism. The similarities and differences in alkalitolerance-related genes among alkalitolerant/alkaliphilic Bacillus species highlight the complex mechanism of pH homeostasis. The B. lehensis G1 genome was also mined for proteins and enzymes with potential viability for industrial and commercial purposes.