In vitroassessment of green polyhydroxybutyrate/chitosan blend loaded with kaempferol nanocrystals as a potential dressing for infected wounds.

Despite the major medical advancements in recent decades, treating infected wounds successfully remains a challenge. In this research, a functional blend of Polyhydroxybutyrate (PHB) and Chitosan (Cs) was developed for wound infection mitigation with tailored biological and physicochemical properties. Water insoluble kaempferol (KPF) was pre-formulated to water soluble KPF nanocrystals (KPF-NCs) with fine particle size of 145 ± 11 nm, and high colloidal stability (-31 ± 0.4 mV) to improve its drug transdermal delivery. PHB-Cs-KPF-NCs (1:2 ratio) film owned the best physical properties in terms of high breathability, thermal stability and mechanical strength (33 ± 1 MPa). Besides, XRD and FTIR findings indicated the interaction between Cs, PHB and KPF, reducing the film crystallinity. The scanning electron microscopy of the film displayed a highly interconnected porous morphology. KPF-NCs were integrated in PHB-Cs matrix with a marked encapsulation efficiency of 96.6%. The enhanced drug-loading film showed a sustain release pattern of KPF-NCs over 48 h. Interestingly, the developed blend possessed an impressive blood clotting capacity within 20 min. Furthermore, we presented a new naturally-sourced mixture of Cs+KPF-NCs with powerful antibacterial effects against MDRStaphylococcus aureusandAcentibacter baumanniiat very low concentrations. The membrane evidenced a remarkable antibacterial naturein vitrowith almost 100% cell viability reduction against the study strains after 48 h. By virtue of these advantages, this green blend is highly proposed for optimal wound care.

Polyhydroxyalkanoate nanoparticles produced by marine bacteria cultivated on cost effective Mediterranean algal hydrolysate media.

Algae are omnipresent in all seas and oceans, which make thema target for many applications such as bio-fertilizers, fish feeding and removal of heavy metals. In the present study, different algal species were examined as sustainable alternatives substrates for PHA production by Halomonas sp. Several media simulations were utilized to achieve high polymer productivity. The maximum poly(3-hydroxybutyrate) (PHB) concentrations were determined by using Corallina mediterranea hydrolysates as a carbon and nitrogen source. The isolates Halomonas pacifica ASL10 and Halomonas salifodiane ASL11 were found to be able to produce PHA by 67 % wt and 63 % wt CDW, respectively. PHB nanoparticles (NPs) had high zeta potential values and small particle sizes. These properties make it suitable for several drug delivery and pharmaceutical applications. Interestingly, NPs showed a potent antibacterial activity against several reference strains. The antibacterial efficacy of PHA-NPs has not been previously studied, thus this study opens a promising use of PHA-NPs.

Post-Synthetic Enzymatic and Chemical Modifications for Novel Sustainable Polyesters.

Because of their biodegradability, compostability, compatibility and flexible structures, biodegradable polymers such as polyhydroxyalkanoates (PHA) are an important class of biopolymers with various industrial and biological uses. PHAs are thermoplastic polyesters with a limited processability due to their low heat resistance. Furthermore, due to their high crystallinity, some PHAs are stiff and brittle. These features result sometimes in very poor mechanical characteristics with low extension at break values which limit the application range of some natural PHAs. Several in vivo approaches for PHA copolymer modifications range from polymer production to enhance PHA-based material performance after synthesis. The methods for enzymatic and chemical polymer modifications are aiming at modifying the structures of the polyesters and thereby their characteristics while retaining the biodegradability. This survey illustrates the efficient use of enzymes and chemicals in post-synthetic PHA modifications, offering insights on these green techniques for modifying and improving polymer performance. Important studies in this sector will be reviewed, as well as chances and obstacles for their stability and hyper-production.

Polyhydroxyalkanoates (PHA) from Halomonas pacifica ASL10 and Halomonas salifodiane ASL11 isolated from Mariout salt lakes.

Two novel PHA producing bacterial strains were chosen out of 12 strains collected from Mariout salt lakes. Analysis of 16srRNA gene sequence of the two new strains revealed 95.38% and 98.78% similarity to that of Halomonas pacifica and Halomonas salifodiane, respectively. A maximum polymer productivity of 6.9 g/l and 7.1 g/l was recorded by ASL10 and ASL11, respectively. Furthermore, a pH of 7 contributed to the highest polymer production for both strains. Interestingly, both ASL10 and ASL11showed a great ability to tolerate salinity up to 17 g/l NaCL. Moreover, both promising isolates were able to degrade crude oil efficiently by degradation percentages of 69.2% and 67.3% for ASL10 and ASL11, respectively. GCMS, FTIR, NMR, XRD and thermal properties were performed for poly (3 HV-co-3HB) characterization.

Ribosomal proteins as a possible tool for blocking SARS-COV 2 virus replication for a potential prospective treatment.

Coronavirus disease (COVID-19) is caused by SARS-COV2 and has resulted in more than four million cases globally and the death cases exceeded 300,000. Normally, a range of surviving and propagating host factors must be employed for the completion of the infectious process including RPs. Viral protein biosynthesis involves the interaction of numerous RPs with viral mRNA, proteins which are necessary for viruses replication regulation and infection inside the host cells. Most of these interactions are crucial for virus activation and accumulation. However, only small percentage of these proteins is specifically responsible for host cells protection by triggering the immune pathway against virus. This research proposes RPs extracted from bacillus sp. and yeast as new forum for the advancement of antiviral therapy. Hitherto, antiviral therapy with RPs-involving viral infection has not been widely investigated as critical targets. Also, exploring antiviral strategy based on RPs could be a promising guide for more potential therapeutics.

The sustainability of microbial bioplastics, production and applications.

Plastic accumulation has destructive environmental impacts, so the world needs eco-friendly plastic alternatives. Within this context, polyhydroxyalkanoates (PHAs) appear to be real alternatives to the chemical plastics because they are biocompatible and biodegradable. Despite its similar properties to common plastics, PHAs use is still hampered by higher production costs. PHAs are produced by high density fed-batch cultivation, activated sludge, microbial consortia and continuous substrate supply, and a major cost associated with their production is the carbon source used for bacterial fermentation. Therefore, novel carbon sources have been studied for PHA production including, macro algae, peanut oil, crude glycerol and whey. PHAs were applied in myriad fields such as wood production, food packaging, 3D painting, cancer detection, treating ulcers as well as several agricultural and therapeutic applications. In this review, current knowledge of methods and novel carbon sources enhance the sustainability and reliability of PHAs in the prospective future.