Production of lactones for flavoring and pharmacological purposes from unsaturated lipids: an industrial perspective.

The enantiomeric pure and natural (+)-Lactones (C ≤ 14) with aromas obtained from fruits and milk are considered flavoring compounds. The flavoring value is related to the lactones' ring size and chain length, which blend in varying concentrations to produce different stone-fruit flavors. The nature-identical and enantiomeric pure (+)-lactones are only produced through whole-cell biotransformation of yeast. The industrially important γ-decalactone and δ-decalactone are produced by a four-step aerobic-oxidation of ricinoleic acid (RA) following the lactonization mechanism. Recently, metabolic engineering strategies have opened up new possibilities for increasing productivity. Another strategy for increasing yield is to immobilize the RA and remove lactones from the broth regularly. Besides flavor impact, γ-, δ-, ε-, ω-lactones of the carbon chain (C8-C12), the macro-lactones and their derivatives are vital in pharmaceuticals and healthcare. These analogues are isolated from natural sources or commercially produced via biotransformation and chemical synthesis processes for medicinal use or as active pharmaceutical ingredients. The various approaches to biotransformation have been discussed in this review to generate more prospects from a commercial point of view. Finally, this work will be regarded as a magical brick capable of containing both traditional and genetic engineering technology while contributing to a wide range of commercial applications.

Efficient remediation of meropenem using Bacillus tropicus EMB20 ß-lactamase immobilized on magnetic nanoparticles.

Reducing antibiotic pollution in the environment in essential to preserve the effectiveness of the available antibiotics. In the present study, ß-lactamase from Bacillus tropicus EMB20 was immobilized onto magnetic nanoparticles (Fe3O4) through covalent coupling method. The nanoconjugate was structurally characterized using SEM, FTIR, UV-spectrometry, and XRD diffraction analyses. The prepared enzyme nanoconjugate was thereafter used for remediation of meropenem (Mer) and showed complete removal of 10 mgL-1 Mer within 3 h of treatment. Moreover, the immobilized enzyme was successfully recovered and reused for up to 5 cycles with 57% removal efficiency. The immobilized preparation was also observed to be effective in the removal of higher Mer concentrations of 25 and 50 mgL-1 with 79% and 75% removal efficiency, respectively. The major hydrolyzed product of Mer was found to be opened-lactam ring structure with m/z 402.16. The hydrolyzed product(s) were observed to be non-toxic as revealed through microbial MTT, confocal microscopy, and growth studies. Under the mixed conditions of 50 mgL-1 ampicillin (Amp), 10 mgL-1 amoxicillin (Amox) and, Mer, the nanoconjugate showed simultaneous complete removal of Amp and Mer, while 49% Amox removal was detected after 3 h of treatment. Moreover, the nanoconjugates also showed concomitant complete removal of antibiotic mixture with in 2 h from aquaculture wastewater. Overall, the study comes out with an efficient approach for remediation of ß-lactam antibiotics from contaminated systems.

Whole genome sequencing and functional analysis of a novel biofilm-eradicating strain Nocardiopsis lucentensis EMB25.

The process of biofilm formation is intricate and multifaceted, requiring the individual cells to secrete extracellular polymeric substances (EPS) that subsequently aggregate and adhere to various surfaces. The issue of biofilms is a significant concern for public health due to the increased resistance of microorganisms associated with biofilms to antimicrobial agents. The current study describes the whole genome and corresponding functions of a biofilm inhibiting and eradicating actinobacteria isolate identified as Nocardiopsis lucentensis EMB25. The N. lucentensis EMB25 has 6.5 Mbp genome with 71.62% GC content. The genome analysis by BLAST Ring Image Generator (BRIG) revealed it to be closely related to Nocardiopsis dassonvillei NOCA502F. Interestingly, based on orthologous functional groups reflected by average nucleotide identity (ANI) analysis, it was 81.48% similar to N. arvandica DSM4527. Also, it produces lanthipeptides and linear azole(in)e-containing peptides (LAPs) akin to N. arvandica. The secondary metabolite search revealed the presence of major gene clusters involved in terpene, ectoine, siderophores, Lanthipeptides, RiPP-like, and T1PKS biosynthesis. After 24 h of treatment, the cell-free extract effectively eradicates the pre-existing biofilm of P. aeruginosa PseA. Also, the isolated bacteria exhibited antibacterial activity against MRSA, Staphylococcus aureus and Bacillus subtilis bacteria. Overall, this finding offers valuable insights into the identification of BGCs, which contain enzymes that play a role in the biosynthesis of natural products. Specifically, it sheds light on the functional aspects of these BGCs in relation to N. lucentensis.

Superoxide dismutase as multipotent therapeutic antioxidant enzyme: Role in human diseases.

Reactive oxygen species (ROS) is consistently recognized as a threat to living organisms, especially for human beings. For proper working of cellular signaling, functioning, and survival, a strict and balanced level of ROS is necessary. Superoxide dismutase (SOD); a group of metalloenzymes provides an important antioxidant defense mechanism, required to preserve the level of ROS in the body. The enzyme reveals the therapeutic potential against various diseases due to a deficiency in the ROS level. The review illustrates the numerous clinical aspects of SOD in various physiological and pathological conditions such as cancer, diabetes, arthritis, cardiovascular, neurodegenerative diseases, etc., with the mechanism of action. Despite limitations, the SOD enzyme has proved as a powerful tool against diseases, and various forms of conjugates and mimetics have been developed and reported to make it more efficient. Extensive studies need in this direction for use of natural SOD-based therapeutics for the prevention and cure of diseases.

Potent γ-amino butyric acid producing psychobiotic Lactococcus lactis LP-68 from non-rhizospheric soil of Syzygium cumini (Black plum).

Gamma amino butyric acid (GABA) is a chemical messenger that plays a significant role in muscle relaxation and brain health. Certain lactic acid bacteria (LAB) produce significant levels of GABA and thus act as potential psychobiotic cultures. In the present study, LAB were isolated from non-rhizospheric soil sample of Syzygium cumini (Black plum). A total of 57 LAB were isolated on the basis of their morphological and acid producing characteristic on de Man Rogosa Sharpe (MRS) agar. Only seven isolates were found to produce GABA (0.09-1.13 gL-1) in MRS broth and were identified as Lactococcus. However, L. lactis LP-68 produced highest amount of GABA and was selected for further optimization of culture conditions (pH, temperature and MSG) by response surface methodology (RSM). The optimization resulted in approximately four-fold increase in GABA production (4.11 gL-1). The results indicate that the L. lactis LP-68 can be used as starter culture for production of GABA-enriched functional foods.

Improved production of alkaline and solvent-stable proteases from a halotolerant Exiguobacterium isolate through heterologous expression.

Halophiles are excellent sources of detergent proteases that are attributed to stability in alkaline pH, salts, surfactants, and hydrophobic solvents. The lower enzymatic yields and tedious downstream processes necessitate the search for newer halophilic sources. We have previously reported a halotolerant Exiguobacterium sp. TBG-PICH-001, which secretes solvent-tolerant alkaline protease/s. The present study describes the heterologous expression of two protease genes, namely, rsep metalloprotease (WP_195864791, 1.23 Kb) and tpa serine protease (WP_195864453, 0.879 Kb) genes. These were cloned into the pET 22b + plasmid vector and expressed in Escherichia coli BL21(DE3). The recombinant proteases rsep and tpa showed respective yields of 6.3 and 6.7 IU/mg, 11 and 12-fold higher than the crude native protease/s from TBG-PICH-001. These showed soluble expression at 46 and 32 KDa, respectively. These were purified to homogeneity through Ni-NTA-affinity chromatography. The purified proteases were characterized for properties like pH & temperature optima and stability, substrate specificity, kinetic parameters, and detergent attributes. They showed affinity towards various substrates with a respective Km of 392 and 301 µM towards casein. The recombinant proteases exhibited stability in the alkaline pH (7-10), surfactants, metal ions, detergents, and hydrophobic solvents, rendering their suitability as detergent additives.

Screening of Multitarget-Directed Natural Compounds as Drug Candidates for Alzheimer's Disease Using In Silico Techniques: Their Extraction and In Vitro Validation.

Alzheimer's disease (AD) is a neurodegenerative disorder that impairs neurocognitive function. Acetylcholinesterase (AChE) and ß-site APP cleaving enzyme 1 (BACE1) are the two main proteins implicated in AD. Indeed, the major available commercial drugs (donepezil, rivastigmine, and galantamine) against Alzheimer's are AChE inhibitors. However, none of these drugs are known to reverse or reduce the pathophysiological condition of the disease since there are multiple contributing factors to AD. Therefore, there is a need to develop a multitarget-directed ligand approach for its treatment. In the present study, plant bioactive compounds were screened for their AChE and BACE1 inhibition potential by conducting molecular docking studies. Considering their docking score and pharmacokinetic properties, limonin, peimisine, serratanine B, and withanolide A were selected as the lead compounds. Molecular dynamics simulations of these protein-ligand complexes confirmed the conformational and energetically stabilized enzyme-inhibitor complexes. The inhibition potential of the lead compounds was validated by in vitro enzyme assay. Withanolide A inhibited AChE (IC50 value of 107 µM) and showed mixed-type inhibition. At this concentration, it inhibited BACE1 activity by 57.10% and was stated as most effective. Both the compounds, as well as their crude extracts, were found to have no cytotoxic effect on the SH-SY5Y cell line.

Biodegradation of terephthalic acid using Rhodococcus erythropolis MTCC 3951: Insights into the degradation process, applications in wastewater treatment and polyhydroxyalkanoate production.

Terephthalic acid (TPA) is an endocrine disruptor widely used as a plasticizer and as a monomer in the manufacturing of PET bottles. However, because of various harmful effects on humans and the environment, it is now recognized as a priority pollutant whose environmental level needs to be controlled. In the present work, the TPA biodegradation efficacy of the bacterium Rhodococcus erythropolis (MTCC 3951) was studied in mineral salt media with TPA as the sole carbon and energy source. R. erythropolis was observed to degrade 5 mM and 120 mM TPA within 10 h and 84 h of incubation, respectively. The degradation efficiency was further optimized by varying the culture conditions, and the following optimum conditions were obtained: inoculum size- 5% (v/v), temperature- 30 °C, agitation speed- 200 rpm, and pH- 8.0. The bacterium was found to use an ortho-cleavage pathway for TPA degradation determined based on enzymatic and GC-MS studies. Moreover, during the degradation of TPA, the bacterium was observed to produce polyhydroxyalkanoate (PHA)-a biopolymer. Biodegradation of 120 mM TPA resulted in an accumulation of PHA. The PHA granules were visualized using fluorescence and transmission electron microscopy and were later characterized using FTIR spectroscopy. Furthermore, the robustness of the bacterium was demonstrated by its ability to degrade TPA in real industrial wastewater. Overall, R. erythropolis (MTCC 3951) hold the potential for controlling TPA pollution in the environment and vis-à-vis the production of PHA biopolymer.

Pan-genomic comparison of a potential solvent-tolerant alkaline protease-producing Exiguobacterium sp. TBG-PICH-001 isolated from a marine habitat.

The identification and applicability of bacteria are inconclusive until comprehended with genomic repositories. Our isolate, Exiguobacterium sp. TBG-PICH-001 exhibited excellent halo- and organic solvent tolerance with simultaneous production of alkaline protease/s (0.512 IU/mL). The crude protease (1 IU) showed a 43.57% degradation of whey protein. The bulk proteins in the whey were hydrolyzed to smaller peptides which were evident in the SDS-PAGE profile. With such characteristics, the isolate became interesting for its genomic studies. The TBG-PICH-001 genome was found to be 3.14 Mb in size with 17 contigs and 47.33% GC content. The genome showed 3176 coding genes, and 2699 genes were characterized for their functionality. The Next-Generation-Sequencing of the genome identified only the isolate's genus; hence we attempted to delineate its species position. The genomes of the isolate and other representative Exiguobacterium spp. were compared based on orthologous genes (Orthovenn2 server). A pan-genomic analysis revealed the match of TBG-PICH-001 with 15 uncharacterized Exiguobacterium genomes at the species level. All these collectively matched with Exiguobacterium indicum, and the results were reconfirmed through phylogenetic studies. Further, the Exiguobacterium indicum genomes were engaged for homology studies rendering 11 classes of protease genes. Two putative proteases (Zinc metalloprotease and Serine protease) obtained from homology were checked for PCR amplification using genomic DNA of TBG-PICH-001 and other Exiguobacterium genomes. The results showed amplification only in the Exiguobacterium indicum genome. These protease genes, after sequencing, were matched with the TBG-PICH-001 genome. Their presence in its whole genome experimentally validated the study. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03796-5.

Inhibition and eradication of Pseudomonas aeruginosa biofilms by secondary metabolites of Nocardiopsis lucentensis EMB25.

Millions of people worldwide have been impacted by biofilm-associated disorders, which are impregnable owing to frequent changes in surface antigens and gene expression. Globally, about 11% of nosocomial infections, including cystic fibrosis, chronic wound infections, and post-surgical infections, are caused by Pseudomonas aeruginosa, the most prevalent Gram-negative bacterial species. Moreover, biofilms are highly resistant to the host's immune system, and exhibit increased tolerance to stress factors such as starvation, dehydration, and antimicrobials. Here, we have isolated a rare halophilic actinobacteria, Nocardiopsis lucentensis EMB25, and utilized the secondary metabolites for inhibition and eradication of P. aeruginosa biofilm. For the first time, N. lucentensis EMB25 bacteria was explored to study the anti-effect of secondary metabolites on pre-established biofilm. The secondary metabolites targeted the quorum sensing pathway and were found to bind to LasR and RhlR, as confirmed via molecular docking. Also, the reduction in virulence factors, rhamnolipids and pyocyanin further supported the study as these two are regulated by LasR and RhlR. In addition, the downregulation of various QS system genes lasA, lasB, rhlA, rhlB, and pqsA confirmed that the secondary metabolites act on two main regulators of the quorum sensing pathway, LasR, and RhlR. The findings of this study support the bioprospecting of previously unknown and extreme-condition actinobacteria as a rich source of novel bioactives against infections caused by bacterial biofilms.

Computational Exploration of Bio-Degradation Patterns of Various Plastic Types.

Plastic materials are recalcitrant in the open environment, surviving for longer without complete remediation. The current disposal methods of used plastic material are inefficient; consequently, plastic wastes are infiltrating the natural resources of the biosphere. The mixed composition of urban domestic waste with different plastic types makes them unfavorable for recycling; however, natural assimilation in situ is still an option to explore. In this research work, we have utilized previously published reports on the biodegradation of various plastics types and analyzed the pattern of microbial degradation. Our results demonstrate that the biodegradation of plastic material follows the chemical classification of plastic types based on their main molecular backbone. The clustering analysis of various plastic types based on their biodegradation reports has grouped them into two broad categories of C-C (non-hydrolyzable) and C-X (hydrolyzable). The C-C and C-X groups show a statistically significant difference in their biodegradation pattern at the genus level. The Bacilli class of bacteria is found to be reported more often in the C-C category, which is challenging to degrade compared to C-X. Genus enrichment analysis suggests that Pseudomonas and Bacillus from bacteria and Aspergillus and Penicillium from fungi are potential genera for the bioremediation of mixed plastic waste. The lack of uniformity in reporting the results of microbial degradation of plastic also needs to be addressed to enable productive growth in the field. Overall, the result points towards the feasibility of a microbial-based biodegradation solution for mixed plastic waste.

Transglutaminase-Polyethyleneimine Nanoflowers Mediated Cellular Delivery of Anti-miR-210 for Effective Glioblastoma Therapy.

Glioblastoma (GBM) is a deadly tumor of the central nervous system (CNS) having a dismal prognosis. miRNA-based therapeutics hold immense potential for GBM therapy; however, its delivery remains a daunting challenge. MicroRNA-210 has been established as a critical oncomiR in GBM. Our group has developed novel, PEI-functionalized transglutaminase-based nanoflowers (TGNFs, ∼61 nm in diameter) for the efficient delivery of anti-miR-210 to glioblastoma cells in vitro. TGNFs show low cytotoxicity to normal human fibroblasts, do not affect the liver and kidney health of CD1 mice, and offer >95% anti-miR encapsulation efficiency, serum stability, and protection against polyanion moieties. Their synthesis is cost-effective and does not involve the application of harsh chemicals. TGNFs successfully delivered anti-miR-210 to glioblastoma cells, decreasing cellular proliferation and migration and increasing apoptosis. Overall, this research highlights the potential of TGNFs as delivery agents in miRNA inhibition therapy and encourages further preclinical studies to explore the potential of miR-210 as a therapeutic target in GBM and various other cancers where the oncogenic role of miR-210 has been well-established.

Mercury bioremediation by mercury accumulating Enterobacter sp. cells and its alginate immobilized application.

The effective microbial remediation of the mercury necessitates the mercury to be trapped within the cells without being recycled back to the environment. The study describes a mercury bioaccumulating strain of Enterobacter sp., which remediated mercury from the medium simultaneous to its growth. The transmission electron micrographs and electron dispersive X-ray analysis revealed the accumulation of remediated mercury as nano-size particles in the cytoplasm as well as on the cell wall. The Enterobacter sp. in the present work was able to accumulate mercury, without being engineered in its native form. The possibility of recovering the accumulated mercury from the cells is also indicated. The applicability of the alginate immobilized cells in removing mercury from synthetic and complex industrial effluent in a batch mode was amply demonstrated. The initial load of 7.3 mg l(-1) mercury in the industrial effluent was completely removed in 72 h. The cells immobilized in calcium alginate were similarly effective in the complete removal of 5 mg l(-1) HgCl(2) of mercury from the synthetic effluent in less than 72 h. The immobilized cells could be reused for multiple cycles.

Investigation of Streptomyces sp. Strain EMB24 Secondary Metabolite Profile Has Unraveled Its Extraordinary Antibacterial Potency Against Drug-Resistant Bacteria.

With the overuse and misuse of antibiotics amid COVID-19 pandemic, the antimicrobial resistance, which is already a global challenge, has accelerated its pace significantly. Finding novel and potential antibiotics seems one of the probable solutions. In this work, a novel Streptomyces sp. strain EMB24 was isolated and found to be an excellent source of antimicrobials as confirmed by agar-plug assay. It showed antibacterial activity against infection-causing bacteria, namely Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. In addition, Streptomyces sp. strain EMB24 inhibited the growth methicillin-resistant Staphylococcus aureus (MRSA), tetracycline-resistant Neisseria gonorrhoeae, and ampicillin-resistant Neisseria gonorrhoeae. Furthermore, to get deep insights about the genome and biosynthetic gene clusters producing antibiotics, whole genome sequencing was done. The strain EMB24 is closely related to the Streptomyces longispororuber as revealed by phylogenetic analysis which is a potential source of antibiotics and pigments as undecylprodigiosin and metacycloprodigiosin belonging to the class prodigiosin. Naphthyridinomycin, alkylresorcinols, desferrioxamine B and E, venezuelin, aborycin, MS-271, and siamycin are potent therapeutics that shared 100% similarity with the reference strain as revealed by the online antiSMASH tool.

Insights from the genome sequence of Bacillus tropicus EMB20, an efficient ß-lactamase-producing bacterium.

We report here the whole-genome sequence of ß-lactamase-producing bacteria Bacillus tropicus EMB20. The genome sequence of Bacillus tropicus EMB20 has a size of 5.8 Mb (G + C content of 35.52%) with 5593 coding DNA sequences (CDSs), 108 tRNA, and 14 rRNA operons. The bacterium has the unique ability to produce a ß-lactamase enzyme with high activity. ß-Lactamases are one of the most common causes of antimicrobial resistance as these enzymes inactivate almost all ß-lactam antibiotics. The antibiotic susceptibility test showed that the B. tropicus EMB20 is producing ß-lactamase and can degrade the ß-lactam antibiotics. Further, the antibiotic degradation potential of this bacteria was confirmed by growing the bacteria in the presence of varying concentrations of ß-lactam antibiotic, amoxicillin. The bacteria were able to hydrolyze amoxicillin up to 50 mg/L in 4 h. Furthermore, the analyses of the genome revealed the presence of multiple ß-lactamase genes, possibly involved in antibiotic degradation. The availability of the genome sequence will provide further insights into the mechanism of antimicrobial resistance by ß-lactamase-producing bacteria. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03395-w.

Alzheimer's disease and its treatment by different approaches: A review.

Alzheimer's disease (AD) is a neurodegenerative disorder that impairs mental ability development and interrupts neurocognitive function. This neuropathological condition is depicted by neurodegeneration, neural loss, and development of neurofibrillary tangles and Aß plaques. There is also a greater risk of developing AD at a later age for people with cardiovascular diseases, hypertension and diabetes. In the biomedical sciences, effective treatment for Alzheimer's disease is a severe obstacle. There is no such treatment to cure Alzheimer's disease. The drug present in the market show only symptomatic relief. The cause of Alzheimer's disease is not fully understood and the blood-brain barrier restricts drug efficacy are two main factors that hamper research. Stem cell-based therapy has been seen as an effective, secure, and creative therapeutic solution to overcoming AD because of AD's multifactorial nature and inadequate care. Current developments in nanotechnology often offer possibilities for the delivery of active drug candidates to address certain limitations. The key nanoformulations being tested against AD include polymeric nanoparticles (NP), inorganic NPs and lipid-based NPs. Nano drug delivery systems are promising vehicles for targeting several therapeutic moieties by easing drug molecules' penetration across the CNS and improving their bioavailability. In this review, we focus on the causes of the AD and their treatment by different approaches.

New threatening of SARS-CoV-2 coinfection and strategies to fight the current pandemic.

Coronavirus disease (COVID-19) is a global pandemic. The COVID-19 outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has overloaded healthcare systems that need medication to be rapidly established, at least to minimize the incidence of COVID-19. The coinfection with other microorganisms has drastically affected human health. Due to the utmost necessity to treat the patient infected with COVID-19 earliest, poor diagnosis and misuse of antibiotics may lead the world where no more drugs are available even to treat mild infections. Besides, sanitizers and disinfectants used to help minimize widespread coronavirus infection risk also contribute to an increased risk of antimicrobial resistance. To ease the situation, zinc supplements' potentiality has been explored and found to be an effective element to boost the immune system. Zinc also prevents the entry of the virus by increasing the ciliary beat frequency. Furthermore, the limitations of current antiviral agents such as a narrow range and low bioavailability can be resolved using nanomaterials, which are considered an important therapeutic alternative for the next generation. Thus, the development of new antiviral nanoagents will significantly help tackle many potential challenges and knowledge gaps. This review paper provides profound insight into how COVID-19 and antimicrobial resistance (AMR) are interrelated and the possible implications and current strategies to fight the ongoing pandemic.

Recent strategies for inhibiting multidrug-resistant and ß-lactamase producing bacteria: A review.

ß-lactam antibiotics are one of the most commonly used drugs for treating bacterial infections, but their clinical effectiveness has been severely affected with bacteria developing resistance against their action. Production of ß-lactamase enzymes by bacteria that can degrade ß-lactams is the most common mechanism of acquiring such resistance, leading to the emergence of multiple-drug resistance in them. Therefore, the development of efficient approaches to combat infections caused by ß-lactamase producing and multidrug-resistant bacteria is the need of the hour. The present review attempts to understand such recent strategies that are in line for development as potential alternatives to conventional antibiotics. We find that apart from efforts being made to develop new antibiotics, several other approaches are being explored, which can help tackle infections caused by resistant bacteria. This includes the development of plant-based drugs, antimicrobial peptides, nano-formulations, bacteriophage therapy, use of CRISPR-Cas9, RNA silencing and antibiotic conjugates with nanoparticles of antimicrobial peptides. The mechanism of action of these novel approaches and potential issues limiting their translation from laboratory to clinics is also discussed. The review is important from an interesting knowledge base which can be useful for researchers working in this domain.

Microbial Nano-Factories: Synthesis and Biomedical Applications.

In the recent times, nanomaterials have emerged in the field of biology, medicine, electronics, and agriculture due to their immense applications. Owing to their nanoscale sizes, they present large surface/volume ratio, characteristic structures, and similar dimensions to biomolecules resulting in unique properties for biomedical applications. The chemical and physical methods to synthesize nanoparticles have their own limitations which can be overcome using biological methods for the synthesis. Moreover, through the biogenic synthesis route, the usage of microorganisms has offered a reliable, sustainable, safe, and environmental friendly technique for nanosynthesis. Bacterial, algal, fungal, and yeast cells are known to transport metals from their environment and convert them to elemental nanoparticle forms which are either accumulated or secreted. Additionally, robust nanocarriers have also been developed using viruses. In order to prevent aggregation and promote stabilization of the nanoparticles, capping agents are often secreted during biosynthesis. Microbial nanoparticles find biomedical applications in rapid diagnostics, imaging, biopharmaceuticals, drug delivery systems, antimicrobials, biomaterials for tissue regeneration as well as biosensors. The major challenges in therapeutic applications of microbial nanoparticles include biocompatibility, bioavailability, stability, degradation in the gastro-intestinal tract, and immune response. Thus, the current review article is focused on the microbe-mediated synthesis of various nanoparticles, the different microbial strains explored for such synthesis along with their current and future biomedical applications.

Phytochemical delivery through nanocarriers: a review.

In recent times, phytochemicals encapsulated or conjugated with nanocarriers for delivery to the specific sites have gained considerable research interest. Phytochemicals are mostly plant secondary metabolites which reported to be beneficial for human health and in disease theraphy. However, these compound are large size and polar nature of these compounds, make it difficult to cross the blood-brain barrier (BBB), endothelial lining of blood vessels, gastrointestinal tract and mucosa. Moreover, they are enzymatically degraded in the gastrointestinal tract. Therefore, encapsulation or conjugation of these compounds with nanocrriers could be an alternate way to enhance their bioefficacy by influencing their gastrointestinal stability, rate of absorption and dispersion. This review presents an overview of nanocarriers alternatives which improves therapeutic value and avoid toxicity, by releasing bioactive compounds specifically at target tissues with enhanced stability and bioavailability. Future investigations may emphasize on deciphering the structural changes in nanocarriers during digestion and absorption, the difference between in-vitro and in-vivo digestion simulations, and impact of nanocarriers on the metabolism of phytochemicals.