Reusable cellulose-based biosorbents for efficient iodine adsorption by economic microcrystalline cellulose production from walnut shell.

Sustainable management of walnut shell (WS) for the extraction of cellulose and preparation of cellulose-based biosorbents of iodine was carried out as a new approach to simultaneously solve the environmental challenge of agricultural solid waste and iodine-contaminated water. A rapid recyclable nitric acid treatment and NaOH-H2O2 alkaline-peroxide treatment of WS (33 % cellulose) extracted pure microcrystalline (Cac) and impure cellulose (Cal) with a 21.70 % and 47.37 % isolation yield, respectively. The techno-economic assessment of cellulose production showed a net profit of 9.02 $/kg for Cac, whereas it was estimated as negative for Cal. The simultaneous carbonization and magnetization of Cac at 550 °C resulted in an amorphous, magnetic cellulose-derived biochar (MB550Cac) with a BET specific surface area of 12.64 m2/g, decorated with scattered irregular Fe3O4 microparticles. The adsorption capacity of MB550Cac for iodine was 555.63 mg/g, which was lost only 17.45 % after six successful cycles of regeneration. Freundlich isotherm model sufficiently described the reversible iodine adsorption on the heterogenous surface. The adsorption kinetics followed the pseudo-second-order model. Further, the adsorption thermodynamics demonstrated spontaneous and favorable adsorption. These findings suggest the valorization of WS to commercially produce cellulose and MB550Cac as a sustainable, efficient biosorbent with a good application prospect in wastewater treatment.

Living Lactobacillus-ZnO nanoparticles hybrids as antimicrobial and antibiofilm coatings for wound dressing application.

Probiotic bacteria are able to produce antimicrobial substances as well as to synthesize green metal nanoparticles (NPs). New antimicrobial and antibiofilm coatings (LAB-ZnO NPs), composed of Lactobacillus strains and green ZnO NPs, were employed for the modification of gum Arabic-polyvinyl alcohol-polycaprolactone nanofibers matrix (GA-PVA-PCL) against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. The physicochemical properties of ZnO NPs biologically synthesized by L. plantarum and L. acidophilus, LAB-ZnO NPs hybrids and LAB-ZnO NPs@GA-PVA-PCL were studied using FE-SEM, EDX, EM, FTIR, XRD and ICP-OES. The morphology of LAB-ZnO NPs hybrids was spherical in range of 4.56-91.61 nm with an average diameter about 34 nm. The electrospun GA-PVA-PCL had regular, continuous and without beads morphology in the scale of nanometer and micrometer with an average diameter of 565 nm. Interestingly, the LAB not only acted as a biosynthesizer in the green synthesis of ZnO NPs but also synergistically enhanced the antimicrobial and antibiofilm efficacy of LAB-ZnO NPs@GA-PVA-PCL. Moreover, the low cytotoxicity of ZnO NPs and ZnO NPs@GA-PVA-PCL on the mouse embryonic fibroblasts cell line led to make them biocompatible. These results suggest that LAB-ZnO NPs@GA-PVA-PCL has potential as a safe promising antimicrobial and antibiofilm dressing in wound healing against pathogens.

Pectin/lignocellulose nanofibers/chitin nanofibers bionanocomposite as an efficient biosorbent of cholesterol and bile salts.

A new biosorbent Ca-crosslinked pectin/lignocellulose nanofibers/chitin nanofibers (PLCN) was synthesized for cholesterol and bile salts adsorption from simulated intestinal fluid during gastric-intestinal passage. The physico-chemical properties of PLCN were studied using SEM, FTIR, XRD, DSC and BET. Before gastrointestinal passage, PLCN had an amorphous single-phase, compact structure formed via hydrogen and van der Waals bonds that revealed an irregular shape with the shriveled surface but watery condition and enzymatic digestion led to create a porous structure without destruction because of the water-insoluble nanofibers, therefore increasing the adsorption capacity. The maximum adsorption capacity reached 37.9 and 5578.4 mg/g for cholesterol and bile salts, respectively. Freundlich isotherm model indicated the reversible heterogeneous adsorption of both cholesterol and bile salts on PLCN. Further, their adsorption followed pseudo-second order kinetic model. These results suggest that PLCN has potential as a gastrointestinal-resistant biosorbent for cholesterol and bile salts adsorption applicable in medicine and food industry.

Synthesis and characterization of antimicrobial wound dressing material based on silver nanoparticles loaded gum Arabic nanofibers.

Gum Arabic (GA) is a biocompatible polymer with the necessary requirements for a wound dressing. However, electrospinning of GA is a bottleneck due to its physico-chemical properties. The aim of this study was to fabricate an antimicrobial nanofibers mat from GA with suitable porosity, water absorption, water vapor permeability and mechanical strength. For this purpose, the composition of polycaprolacton (PCL)-coated GA-polyvinyl alcohol (PVA) nanofibers mat was optimized based on the possible highest porosity, water absorption and water vapor permeability, and then silver nanoparticles (AgNPs) loaded nanofibers mat was prepared based on this composition. The synthesis of AgNPs was supported by UV-vis and ICP analyses. The structure of mat and its constituents were characterized by FE-SEM, XRD and FTIR. The results showed that the average diameter of nanofibers was in the range of 150 to 250 nm with the porosity, water absorption and water vapor permeability of 37.34%, 547.30% and 2235.50 g/m2.day, respectively. The antimicrobial activity of mat against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans was proved. Moreover, the cytotoxicity of mat showed the good biocompatibility for the mouse embryonic fibroblast cells. This study introduced PCL-coated GA-PVA-AgNPs as an effective antimicrobial mat alternative for commercial wound dressing.

A comparative study on schizophyllan and chitin nanoparticles for ellagic acid delivery in treating breast cancer.

In this study, following encapsulation of ellagic acid (EA), an anti-cancer agent, loaded in schizophyllan (EA/SPG-NP) and chitin (EA/Ch-NP) nanoparticles, its release in 95% ethanol, and different mediums of digestive systems with pH ranging 1.5 to 7.4, were examined before investigating for treatment of breast cancer MCF-7cells. Following synthesis, the EA was characterized by FT-IR, SEM, XRD, DLS and zeta potential analysis. Loading capacity of schizophyllan and chitin were 30.08 and 79.52%, respectively, while SEM images indicated respective size distributions of 217.8 and 39.82 nm, with the corresponding zeta potentials being +27 and -9.14 mV. As EA was loaded in nanoparticles, antioxidant activity, examined by DPPH method, of the free EA was found to be higher than both EA/SPG-NP and EA/Ch-NP, but lower than the latter at 7.4 pH. Interestingly, scavenging activities for EA and EA/SPG-NP reduced for higher pH. The MTT cytotoxicity indicated that EA/SPG-NP and EA/Ch-NP inhibited effectively cell growth of breast cancer cell lines at IC50 of 60 and 115 µg/ml, respectively.

Co-microencapsulation of Lactobacillus plantarum and DHA fatty acid in alginate-pectin-gelatin biocomposites.

The aim of this study was to investigate the co-microencapsulation of Lactobacillus plantarum and DHA-rich oil in a novel gastrointestinal-resistant biocomposite composed of alginate, pectin and gelatin. The optimal biocomposite consisted of 1.06% alginate, 0.55% pectin and 0.39% gelatin showed 88.66% survivability of the microencapsulated cells compared to the free cells (50.36%). In addition, co-microencapsule containing probiotic and DHA fatty acid was synthesized and physicochemically analyzed using SEM, FTIR, TGA, XRD. The results from SEM clearly confirmed that cells were completely entrapped in the matrix and DHA increased smoothness and compactness of the surface of the particles. FTIR spectra revealed the formation of hydrogen and Van der Waals bonds between macromolecules and the core materials. X-ray pattern of co-microencapsules identified amorphous structure compared to capsules containing only DHA or probiotic. TGA analysis revealed the thermal stability of DHA-loaded capsules compared to un-loaded ones.

Pectin-non-starch nanofibers biocomposites as novel gastrointestinal-resistant prebiotics.

Incorporation of nanofibers of chitin (NC), lignocellulose (NLC) and bacterial cellulose (BNC) in pectin was studied to improve prebiotic activity and gastrointestinal resistance of the pectin-nanofibers biocomposites for protection of probiotics under simulated gastrointestinal conditions. The biocomposites were prepared using various compositions of pectin and nanofibers, which were designed using D-optimal mixture method. The incorporation of the nanofibers in pectin led to a slow degradation of the pectin-nanofibers biocomposites in contrast to their rapid swelling. AFM analysis indicated the homogenous distribution of interconnected nanofibers network structure in the pectin-nanofibers biocomposite. FTIR spectra demonstrated fabrication of the biocomposites based on the inter- and intra-molecular hydrogen bonding and ionic interaction of pectin-Ca2+. XRD patterns revealed the amorphous structures of the biocomposites as compared to the crystalline structures of the nanofibers. Among the compositions, the optimal compositions were as follows: 60% pectin+40% NC, 50% pectin+50% NLC and 60% pectin+40% BNC, where the prebiotic score, probiotic survival under simulated gastric and intestinal conditions were optimum. The optimal biocomposite pectin-NC exhibited the highest survival of the entrapped probiotic bacteria under simulated gastric (97.7%) and intestinal (95.8%) conditions when compared with the corresponding to free cells (76.2 and 73.4%).

Bacterial nanocellulose-pectin bionanocomposites as prebiotics against drying and gastrointestinal condition.

Various encapsulating materials have been suggested to protect probiotics, but the potential of nanomaterials is yet to be exploited. This study aimed to improve the survivability of Bacillus coagulans entrapping into bionanocomposites comprising of bacterial nanocellulose (BNC), pectin and Schizophyllum commune extract were investigated as new matrices to protect probiotics. The bionanocomposite design was optimized to obtain the highest prebiotic score and survivability of probiotic under drying process and gastrointestinal condition using the simplex-lattice mixture method. The optimal bionanocomposite formulation was obtained by mixing 20% pectin with 80% BNC. High survival rate of B. coagulans after microwave drying (99.43%) and sequential digestion under stimulated gastrointestinal fluids (94.76%) with optimum prebiotic score for B. coagulans (1.00) and for Escherichia coli (0.99), were obtained. Nanoscale properties of BNC, high crystallinity and available surface area resulted in high probiotic protection. Stability test during storage period at ambient temperature, 4°C and -20°C performed viability reduction, respectively, 1.3, 1.7 and 1.8 log CFU/g, which inferred the optimal bionanocomposite could be candidate as useful probiotics protection system in a variety of temperature during long time.

Optimization of biomass and biokinetic constant in Mazut biodegradation by indigenous bacteria BBRC10061.

Optimization based on appropriate parameters can be applied to improve a process. Mazut degradation as a critical issue in environment requires optimization to be efficiently done. To provide biodegradation conditions, experiments were designed on the least interactions among levels of parameters consisting of pH, Tween 80, glucose, phosphorous source, nitrogen source, and time. Kinetic constants and biomass were calculated based on 16 assays, designed using Taguchi method, which constructed various mazut biodegradation conditions. Kinetics of mazut degradation by newly isolated bacteria Enterobacter cloacae closely followed second order kinetic model. Results of the 16 experiments showed that biomass was in the range of 0.019 OD600 to 2.75 OD600, and biokinetic constant was in the range of 0.2 × 10(-5) L/ (mg day) to 10(-4) L/ (mg day). Optimal level for each parameter was obtained through data analysis. For optimal biomass equal to 2.75 OD600, optimal pH, Tween80, glucose, phosphorous source, and time were 8.3, 4 g/L, 4 g/L, 9 g/L, and 10 days, respectively. For biokinetic constant equal to 1.2 × 10(-4) L/ (mg day), optimal pH, Tween80, glucose, phosphorous source, and nitrogen source were 8.3, 1 g/L, 4 g/L, 1 g/L, and 9 g/L, respectively. The optimum levels for biomass and biokinetic constant were the same except the levels of the Tween 80, and phosphorous source. Consequently, mazut may be more degraded with adjusting the conditions on the optimum condition.

Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: improving and kinetic investigation.

Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration was assayed based on gradual addition method. Also different kinetic models were used to evaluate kinetics of the process. Results showed that gradual addition method has been a beneficial technique for improvement of mazut degradation because bacterial induction to produce biosurfactant and essential enzymes for cracking mazut was higher during process. Although addition of more mazut increased the rate of biodegradation but percentage of degradation decreased. pH of medium decreased during biodegradation period while electric potential increased. Also the biodegradation kinetics was not fitted with the biokinetic models; therefore kinetics of biodegradation of mazut has to be studied by new models.