Purification and characterization of extracellular tannase from Aspergillus fumigatus MA using Syzigium cumini leaves under solid state fermentation.

This study reports the tannase purification produced by a tannery effluent-originated fungal isolate i.e., Aspergillus fumigatus MA under solid state fermentation (SSF) condition. Purification of tannase from culture filtrate was attained using ammonium sulfate precipitation with subsequent diethylaminoethyl (DEAE)-cellulose mediated ion exchange chromatographic technique. Fractional precipitation of the culture filtrate with 60-80% ammonium sulfate yielded 80.9% recovery of tannase with 6.16-fold purification. The enzyme fractions were collected and eluted as a single peak using 0.5 M NaCl-gradient concentration. DEAE-cellulose column chromatography results in overall 23-fold purification with 27.6% recovery of the enzyme. SDS-PAGE analysis of purified tannase confirmed the presence of a single band of protein with a molecular mass equivalent to 66.2 kDa. The highest activity of tannase was observed at optimum pH ranged between 5.0-6.0 whereas, the tannase stability (>80%) was observed at 4.0 to 7.0 pH ranges. The purified tannase activity was found to be optimally active at 30 °C whereas stability (>90%) was accomplished between 30-50 °C temperature. The Km and Vmax were found to be 1.61 × 10-3 M and 1.04 mM respectively. These properties suggest the potential of the enzyme to be utilized in various food, feed, and pharmaceutical sectors.

Priestia flexa KS1: A new bacterial strain isolated from human faeces implicated in mucin degradation.

The human gut acts as a habitat for diverse microbial communities, including mucin utilizers that play a significant role in host health and diseases. In this study, a gram-positive, rod-shaped mucin degrading bacterium was isolated from human faeces that belonged to the Priestia flexa species. Priestia isolate was analyzed for mucin-degrading ability and found that the KS1 strain could grow on mucin as the sole carbon source. The experimental results of the mucolytic zone around the colony and a 58% decrease in carbohydrate concentration confirmed the ability of Priestia to degrade mucin. The intracellular and extracellular glycosidase assay data supported the above results suggesting the ability of P. flexa to produce glycan hydrolysis enzymes that convert complex mucin oligosaccharide chains into simple glycans. The survival ability of the KS1 strain in simulated gastrointestinal conditions revealed that it could tolerate low pH (≥ 50% cell viability at pH 1.0) and 0.5% bile salt concentration (≥ 85% cell viability). The strain showed low hydrophobicity towards n-hexadecane (26.51 ± 0.92%) and xylene (21.71 ± 0.54%). Moreover, the KS1 culture was resistant to cefixime, clavulanic acid/ceftazidime, nafallin, methicillin, trimethoprim, kanamycin, and nalidixic antibiotic. Our results highlight the isolation of P. flexa KS1 strain that degrade mucin under in vitro conditions and show its better acclimatization within the GI environment. Further studies are required to unearth the molecular mechanisms involved in the degradation of mucin oligosaccharides in the human gut, advancing our understanding of health and disease.

Mucolytic bacteria: prevalence in various pathological diseases.

All mucins are highly glycosylated and a key constituent of the mucus layer that is vigilant against pathogens in many organ systems of animals and humans. The viscous layer is organized in bilayers, i.e., an outer layer that is loosely arranged, variable in thickness, home to the commensal microbiota that grows in the complex environment, and an innermost layer that is stratified, non-aspirated, firmly adherent to the epithelial cells and devoid of any microorganisms. The O-glycosylation moiety represents the site of adhesion for pathogens and due to the increase of motility, mucolytic activity, and upregulation of virulence factors, some microorganisms can circumvent the component of the mucus layer and cause disruption in organ homeostasis. A dysbiotic microbiome, defective mucus barrier, and altered immune response often result in various diseases. In this review, paramount emphasis is given to the role played by the bacterial species directly or indirectly involved in mucin degradation, alteration in mucus secretion or its composition or mucin gene expression, which instigates many diseases in the digestive, respiratory, and other organ systems. A systematic view can help better understand the etiology of some complex disorders such as cystic fibrosis, ulcerative colitis and expand our knowledge about mucin degraders to develop new therapeutic approaches to correct ill effects caused by these mucin-dwelling pathogens.

Biogenic synthesis, optimisation and antibacterial efficacy of extracellular silver nanoparticles using novel fungal isolate Aspergillus fumigatus MA.

To eliminate the elaborate processes employed in other non-biological-based protocols and low cost production of silver nanoparticles (AgNPs), this study reports biogenic synthesis of AgNPs using silver salt precursor with aqueous extract of Aspergillus fumigates MA. Influence of silver precursor concentrations, concentration ratio of fungal extract and silver nitrate, contact time, reaction temperature and pH are evaluated to find their effects on AgNPs synthesis. Ultraviolet-visible spectra gave surface plasmon resonance at 420 nm for AgNPs. Fourier transform infrared spectroscopy and X-ray diffraction techniques further confirmed the synthesis and crystalline nature of AgNPs, respectively. Transmission electron microscopy observed spherical shapes of synthesised AgNPs within the range of 3-20 nm. The AgNPs showed potent antimicrobial efficacy against various bacterial strains. Thus, the results of the current study indicate that optimisation process plays a pivotal role in the AgNPs synthesis and biogenic synthesised AgNPs might be used against bacterial pathogens; however, it necessitates clinical studies to find out their potential as antibacterial agents.

Effect of freeze drying process on some properties of Streptococcus thermophilus isolated from dairy products

The present investigation represents the effect of freeze drying on some properties as acid and bile tolerance of Streptococcus thermophilus MTCC 1938 culture isolated from dairy products. The cell paste obtained from milk based medium was freeze dried with a pressure of 50-100 mtorr for 24h at -40ºC. Acid and bile tolerance test exhibited 3.8-4.9 and 3.2-3.8 log counts reduction after freeze drying respectively.

Tannase production by Penicillium atramentosum KM under SSF and its applications in wine clarification and tea cream solubilization

Tannin acyl hydrolase commonly known as tannase is an industrially important enzyme having a wide range of applications, so there is always a scope for novel tannase with better characteristics. A newly isolated tannase-yielding fungal strain identified as Penicillium atramentosum KM was used for tannase production under solid-state fermentation (SSF) using different agro residues like amla (Phyllanthus emblica), ber (Zyzyphus mauritiana), jamun (Syzygium cumini), Jamoa (Eugenia cuspidate) and keekar (Acacia nilotica) leaves. Among these substrates, maximal extracellular tannase production i.e. 170.75 U/gds and 165.56 U/gds was obtained with jamun and keekar leaves respectively at 28ºC after 96 h. A substrate to distilled water ratio of 1:2 (w/v) was found to be the best for tannase production. Supplementation of sodium nitrate (NaNO3) as nitrogen source had enhanced tannase production both in jamun and keekar leaves. Applications of the enzyme were studied in wine clarification and tea cream solubilization. It resulted in 38.05 percent reduction of tannic acid content in case of jamun wine, 43.59 percent reduction in case of grape wine and 74 percent reduction in the tea extract after 3 h at 35ºC.

Tannase Production by Penicillium Atramentosum KM under SSF and its Applications in Wine Clarification and Tea Cream Solubilization.

Tannin acyl hydrolase commonly known as tannase is an industrially important enzyme having a wide range of applications, so there is always a scope for novel tannase with better characteristics. A newly isolated tannase-yielding fungal strain identified as Penicillium atramentosum KM was used for tannase production under solid-state fermentation (SSF) using different agro residues like amla (Phyllanthus emblica), ber (Zyzyphus mauritiana), jamun (Syzygium cumini), Jamoa (Eugenia cuspidate) and keekar (Acacia nilotica) leaves. Among these substrates, maximal extracellular tannase production i.e. 170.75 U/gds and 165.56 U/gds was obtained with jamun and keekar leaves respectively at 28ºC after 96 h. A substrate to distilled water ratio of 1:2 (w/v) was found to be the best for tannase production. Supplementation of sodium nitrate (NaNO3) as nitrogen source had enhanced tannase production both in jamun and keekar leaves. Applications of the enzyme were studied in wine clarification and tea cream solubilization. It resulted in 38.05% reduction of tannic acid content in case of jamun wine, 43.59% reduction in case of grape wine and 74% reduction in the tea extract after 3 h at 35°C.

Effect of freeze drying process on some properties of Streptococcus thermophilus isolated from dairy products.

The present investigation represents the effect of freeze drying on some properties as acid and bile tolerance of Streptococcus thermophilus MTCC 1938 culture isolated from dairy products. The cell paste obtained from milk based medium was freeze dried with a pressure of 50-100 mtorr for 24h at -40°C. Acid and bile tolerance test exhibited 3.8-4.9 and 3.2-3.8 log counts reduction after freeze drying respectively.