A Comparison Between Lime And Alkaline Hydrogen Peroxide Pretreatments Of Sugarcane Bagasse For Ethanol Production.

Pretreatment procedures of sugarcane bagasse with lime (calcium hydroxide) or alkaline hydrogen peroxide were evaluated and compared. Analyses were performed using 2 x 2 x 2 factorial designs, with pretreatment time, temperature, and lime loading and hydrogen peroxide concentration as factors. The responses evaluated were the yield of total reducing sugars (TRS) and glucose released from pretreated bagasse after enzymatic hydrolysis. Experiments were performed using the bagasse as it comes from an alcohol/sugar factory and bagasse in the size range of 0.248 to 1.397 mm (12-60 mesh). The results show that when hexoses and pentoses are of interest, lime should be the pretreatment agent chosen, as high TRS yields are obtained for nonscreened bagasse using 0.40 g lime/g dry biomass at 70 degrees C for 36 h. When the product of interest is glucose, the best results were obtained with lime pretreatment of screened bagasse. However, the results for alkaline peroxide and lime pretreatments of nonscreened bagasse are not very different.14845-5

Kinetics Of Lime Pretreatment Of Sugarcane Bagasse To Enhance Enzymatic Hydrolysis.

The objective of this work was to determine the optimum conditions of sugarcane bagasse pretreatment with lime to increase the enzymatic hydrolysis of the polysaccharide component and to study the delignification kinetics. The first stage was an evaluation of the influence of temperature, reaction time, and lime concentration in the pretreatment performance measured as glucose release after hydrolysis using a 2(3) central composite design and response surface methodology. The maximum glucose yield was 228.45 mg/g raw biomass, corresponding to 409.9 mg/g raw biomass of total reducing sugars, with the pretreatment performed at 90°C, for 90 h, and with a lime loading of 0.4 g/g dry biomass. The enzymes loading was 5.0 FPU/dry pretreated biomass of cellulase and 1.0 CBU/dry pretreated biomass of β-glucosidase. Kinetic data of the pretreatment were evaluated at different temperatures (60°C, 70°C, 80°C, and 90°C), and a kinetic model for bagasse delignification with lime as a function of temperature was determined. Bagasse composition (cellulose, hemicellulose, and lignin) was measured, and the study has shown that 50% of the original material was solubilized, lignin and hemicellulose were selectively removed, but cellulose was not affected by lime pretreatment in mild temperatures (60-90°C). The delignification was highly dependent on temperature and duration of pretreatment.163612-2

An integrated approach to obtain xylo-oligosaccharides from sugarcane straw: From lab to pilot scale

Sugarcane straw (SS) is a widely available agricultural processing feedstock with the potential to produce 2nd generation bioethanol and bioproducts, in addition to the more conventional use for heat and/or electrical power generation. In this study, we investigated the operational parameters to maximize the production of xylo-oligosaccharides (XOS) using mild deacetylation, followed by hydrothermal pretreatment. From the laboratory to the pilot-scale, the optimized two-stage pretreatment promoted 81.5% and 70.5% hemicellulose solubilization and led to XOS yields up to 9.8% and 9.1% (w/w of initial straw), respectively. Moreover, different fungal xylanases were also tested to hydrolyze XOS into xylobiose (X2) and xylotriose (X3). GH10 from Aspergillus nidulans performed better than GH11 xylanases and the ratio of the desired products (X2 + X3) increased to 72% due to minimal monomeric sugar formation. Furthermore, a cellulose-rich fraction was obtained, which can be used in other high value-added applications, such as for the production of cello-oligomers313CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP404654/2018-5; 304816/2017-5; 304944/2018-188887.373114/2019-002015/50612-8; 2017/15477-8; 2017/22669-

Structural characterization of sugarcane lignins extracted from different protic ionic liquid pretreatments

Previous studies based on protic ionic liquids have shown them to be effective for extracting lignins from biomass. Moreover, ILs synthesized with amine cations can promote the insertion of nitrogen into lignin, favoring its valorization for industrial applications. In this study, lignins extracted from sugarcane bagasse by eight different PILs were analyzed. Several techniques of characterization were employed (2D HSQC NMR, 31P NMR, GPC, Py-GC/MS, TGA, FTIR, and elemental analysis), seeking a deeper understanding of lignin structure post-PILS treatment. In particular, lignin obtained with acetate and lactate anions with monoethanolamonium cations showed similar structural compositions. Lignins obtained from ethylenediamonium cation combined anions acetate and lactate exhibited relatively higher molecular weights compared to the other lignins studied. The elemental analysis of these lignins further revealed the presence of nitrogen in their structures, suggesting that amination occurred. In this work we used PILs not yet reported in the literature for this purpose, and consequently obtained lignins with specific structures. Overall, our results demonstrated that depending on the PILs used, lignins with distinct properties could be obtained which might be used for value-added applications. This work covered new advances in elucidation of lignin chemical structure and opened a new path for lignin valorization161579592CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP141393/2018-1; 204710/2018-9; 304944/2018-1; 405934/2018-123038.007211/2012-932015/20630-

Xylo-oligosaccharides, fermentable sugars, and bioenergy production from sugarcane straw using steam explosion pretreatment at pilot-scale

This study investigated the production of xylo-oligosaccharides (XOS) from sugarcane straw (SCS) using steam explosion (SE) pretreatment at pilot-scale, as well as co-production of fermentable sugars and lignin-rich residues for bioethanol and bioenergy, respectively. SE conditions 200 °C; 15 bar; 10 min led to 1) soluble XOS yields of up to 35 % (w/w) of initial xylan with ∼50 % of the recovered XOS corresponding to xylobiose and xylotriose, considered the most valuable sugars for prebiotic applications; 2) fermentable glucose yields from the enzymatic hydrolysis of SE-pretreated SCS of up to ∼78 %; 3) increase in the energy content of saccharified SCS residues (16 %) compared to the untreated material. From an integrated biorefinery perspective, it demonstrated the potential use of SCS for the production of value-added XOS ingredients as well as liquid and solid biofuel products.</p

Xylo-oligosaccharides, fermentable sugars, and bioenergy production from sugarcane straw using steam explosion pretreatment at pilot-scale

This study investigated the production of xylo-oligosaccharides (XOS) from sugarcane straw (SCS) using steam explosion (SE) pretreatment at pilot-scale, as well as co-production of fermentable sugars and lignin-rich residues for bioethanol and bioenergy, respectively. SE conditions 200 °C; 15 bar; 10 min led to 1) soluble XOS yields of up to 35 % (w/w) of initial xylan with ∼50 % of the recovered XOS corresponding to xylobiose and xylotriose, considered the most valuable sugars for prebiotic applications; 2) fermentable glucose yields from the enzymatic hydrolysis of SE-pretreated SCS of up to ∼78 %; 3) increase in the energy content of saccharified SCS residues (16 %) compared to the untreated material. From an integrated biorefinery perspective, it demonstrated the potential use of SCS for the production of value-added XOS ingredients as well as liquid and solid biofuel products.</p

Lignins from sugarcane bagasse : renewable source of nanoparticles as Pickering emulsions stabilizers for bioactive compounds encapsulation

Lignin nanoparticles has gained interest in recent years in a wide range of applications due to its unique properties compared to the microsized material. Furthermore, lignin is obtained from lignocellulosic biomass processing and it is still considered a poorly exploited macromolecule due to the heterogeneous nature and low solubility in aqueous medium. This study focus on the comparison between two ways environmentally friendly of obtaining colloidal lignin nanoparticles (LNPs), considering minimal processing steps and employing lignins derived from two sugarcane bagasse pretreatments (alkaline and organosolv). Raw lignins and LNPs were characterized by different techniques such as scanning electron microscopy (SEM), zeta potential, dynamic light scattering (DLS), small-angle X-ray scattering (SAXS) and antioxidant assay in order to evaluate the changes in its morphological, chemical and antioxidant properties. The results showed the formation of spherical-like nanoparticles which sizes were determined by the synthesis method. LNPs obtained from alkaline lignin showed an average diameter varying from 115 to 300 nm, while LNPs obtained from organosolv lignin ranged from 270 to 680 nm, as determined by DLS. All LNPs in aqueous suspension had a zeta potential ranging from −25 to −35 mV, which is considered stable for colloidal systems. The thermal stability properties of micro to nanosized lignins were preserved. The antioxidant capacity against the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical was improved for alkaline-LNPs compared to the raw lignin (IC30 = 12 and 9.9 μg mL−1, respectively), and worsened for organosolv-LNPs compared to the raw lignin (IC30 = 11.4 and 15 μg mL−1, respectively). Furthermore, LNPs were tested as stabilizing agents of Pickering emulsions, used as encapsulation agents of curcumin, a polyphenol with a wide range of pharmacological applications. Organosolv-LNPs were seen to be the most efficient stabilizer, retaining 73% of curcumin in its encapsulated form after 96 h. Therefore, this study demonstrated the potential of nanostructured lignins for bio-based field, and also highlights the influence factors for the choice of methodology and raw lignins over the properties resulted of LNPs140The authors would like to thank Brazilian Biorenewables National Laboratory (LNBR/CNPEM/MCTIC) for all infrastructure available, including the Characterization of Macromolecules (MAC) open access facility, Brazilian Biosciences National Laboratory (LNBIO/CNPEM/MCTIC), in particular, Silvana A. Rocco for NMR analysis (proposal number RMN-22872), Brazilian Nanotechnology National Laboratory (LNNano/CNPEM/MCTIC) for microscopy analysis (proposal numbers TEM-23392 and SEM-23394), Brazilian Synchrotron Light Laboratory (LNLS/CNPEM/MCTIC) for SAXS analysis (proposal number 20180313), Erik N. Medina for Pickering emulsions photographs, Fernanda Mandelli for the help with DPPH assay and Thaynara C. Pin for the help with HSQC result