Effect of different pretreatments on egyptian sugar-cane bagasse saccharification and bioethanol production

AbstractSugar-cane processing generates large amount of bagasse. Disposal of bagasse is critical for both agricultural profitability and environmental protection. Sugar-cane bagasse is a renewable resource that can be used to produce ethanol.In this study, twelve microbial isolates, five bacteria, four yeasts and three filamentous fungi were isolated from sugar-cane bagasse. Bacterial and yeast isolates were selected for their ability to utilize different sugars and cellulose. Chipped and ground bagasse was subjected to different pretreatment methods; physically through steam treatment by autoclaving at 121°C and 1.5bar for 20min and/or different doses of gamma γ irradiation (50 and 70Mrad). Autoclaved pretreated bagasse was further biologically treated through the solid state fermentation process by different fungal isolates; F-66, F-94 and F-98 producing maximum total reducing sugars of 18.4., 26.1 and 20.4g/L, respectively.Separate biological hydrolysis and fermentation (SHF) process for bagasse was done by the two selected fungal isolates; Trichoderma viride F-94 and Aspergillus terreus F-98 and the two yeast isolates identified as Candida tropicalis Y-26 and Saccharomyces cerevisiae Y-39. SHF processes by F-94 and Y-26 produced 226kg of ethanol/ton bagasse while that of F-98 and Y-39 produced 185kg of ethanol/ton bagasse

Enzymatic Synthesis of Glucose Fatty Acid Esters Using SCOs as Acyl Group-Donors and Their Biological Activities

Sugar fatty acid esters, especially glucose fatty acid esters (GEs), have broad applications in food, cosmetic and pharmaceutical industries. In this research, the fatty acid moieties derived from polyunsaturated fatty acids containing single-cell oils (SCOs) (i.e., those produced from Cunninghamella echinulata, Umbelopsis isabellina and Nannochloropsis gaditana, as well as from olive oil and an eicosapentaenoic acid (EPA) concentrate) were converted into GEs by enzymatic synthesis, using lipases as biocatalysts. The GE synthesis was monitored using thin-layer chromatography, FTIR and in situ NMR. It was found that GE synthesis carried out using immobilized Candida antarctica B lipase was very effective, reaching total conversion of reactants. It was shown that EPA-GEs were very effective against several pathogenic bacteria and their activity can be attributed to their high EPA content. Furthermore, C. echinulata-GEs were more effective against pathogens compared with U. isabellina-GEs, probably due to the presence of gamma linolenic acid (GLA) in the lipids of C. echinulata, which is known for its antimicrobial activity, in higher concentrations. C. echinulata-GEs also showed strong insecticidal activity against Aedes aegypti larvae, followed by EPA-GEs, olive oil-GEs and N. gaditana-GEs. All synthesized GEs induced apoptosis of the SKOV-3 ovarian cancer cell line, with the apoptotic rate increasing significantly after 48 h. A higher percentage of apoptosis was observed in the cells treated with EPA-GEs, followed by C. echinulata-GEs, U. isabellina-GEs and olive oil-GEs. We conclude that SCOs can be used in the synthesis of GEs with interesting biological properties

Bioinspired Graphene Oxide–Magnetite Nanocomposite Coatings as Protective Superhydrophobic Antifouling Surfaces

Antifouling (AF) nanocoatings made of polydimethylsiloxane (PDMS) are more cost-efficient and eco-friendly substitutes for the already outlawed tributyltin-based coatings. Here, a catalytic hydrosilation approach was used to construct a design inspired by composite mosquito eyes from non-toxic PDMS nanocomposites filled with graphene oxide (GO) nanosheets decorated with magnetite nanospheres (GO–Fe3O4 nanospheres). Various GO–Fe3O4 hybrid nanofillers were dispersed into the PDMS resin through a solution casting method to evaluate the structure–property relationship. A simple coprecipitation procedure was used to fabricate magnetite nanospheres with an average diameter of 30–50 nm, a single crystal structure, and a predominant (311) lattice plane. The uniform bioinspired superhydrophobic PDMS/GO–Fe3O4 nanocomposite surface produced had a micro-/nano-roughness, low surface-free energy (SFE), and high fouling release (FR) efficiency. It exhibited several advantages including simplicity, ease of large-area fabrication, and a simultaneous offering of dual micro-/nano-scale structures simply via a one-step solution casting process for a wide variety of materials. The superhydrophobicity, SFE, and rough topology have been studied as surface properties of the unfilled silicone and the bioinspired PDMS/GO–Fe3O4 nanocomposites. The coatings’ physical, mechanical, and anticorrosive features were also taken into account. Several microorganisms were employed to examine the fouling resistance of the coated specimens for 1 month. Good dispersion of GO–Fe3O4 hybrid fillers in the PDMS coating until 1 wt % achieved the highest water contact angle (158° ± 2°), the lowest SFE (12.06 mN/m), micro-/nano-roughness, and improved bulk mechanical and anticorrosion properties. The well-distributed PDMS/GO–Fe3O4 (1 wt % nanofillers) bioinspired nanocoating showed the least biodegradability against all the tested microorganisms [Kocuria rhizophila (2.047%), Pseudomonas aeruginosa (1.961%), and Candida albicans (1.924%)]. We successfully developed non-toxic, low-cost, and economical nanostructured superhydrophobic FR composite coatings for long-term ship hull coatings. This study may expand the applications of bio-inspired functional materials because for multiple AF, durability and hydrophobicity are both important features in several industrial applications