Effects of initial corncob particle size on the short-term composting for preparation of cultivation substrates for Pleurotus ostreatus.

The short-term composting based on corncob for preparing Pleurotus ostreatus cultivation medium originated from agricultural production practices and so lacked systematic investigation. In this study, the influences of a Dafen (15 mm, DFT) and Xiaofen (5 mm, XFT) initial particle size (IPS) of corncob on the microbial succession and compost quality were examined. Results demonstrated that XFT compost was better suited for mushroom cultivation due to its high biological efficiency of 70 % and the absence of contamination. The composting microbes differed significantly between the DFT and XFT composts. During composting, the genera of Bacillus, Acinetobacter, Lactobacillus, Streptomyces, and Paenibacillus were majorly found in the DFT compost, while Acinetobacter, Lactobacillus, Puccinia, Bacteroides, and Bacillus genera dominated the XFT compost. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that throughout the thermophilic phase, XFT compost had much greater relative abundances of sequences relevant to energy, carbohydrate, and amino acid metabolism than DFT compost. Analysis of network correlations and Mantel tests indicated that IPS reduction could increase microbial interactions. Overall, adjusting the IPS of corncob to 5 mm increased microbial interactions, improved compost quality, and thereby boosted the P. ostreatus yield. These findings will be pertinent in optimizing the composting process of cultivation medium for P. ostreatus.

Production of cello-oligosaccharides from corncob residue by degradation-synthesis reactions.

The cellulose-rich corncob residue (CCR) is an abundant and renewable agricultural biomass that has been under-exploited. In this study, two strategies were compared for their ability to transform CCR into cello-oligosaccharides (COS). The first strategy employed the use of endo-glucanases. Although selected endo-glucanases from GH9, GH12, GH45, and GH131 could release COS with degrees of polymerization from 2 to 4, the degrading efficiency was low. For the second strategy, first, CCR was efficiently depolymerized to glucose and cellobiose using the cellulase from Trichoderma reesei. Then, using these simple sugars and sucrose as the starting materials, phosphorylases from different microorganisms were combined to generate COS to a level up to 100.3 g/L with different patterns and degrees of polymerization. Using tomato as a model plant, the representative COS obtained from BaSP (a sucrose phosphorylase from Bifidobacterium adolescens), CuCbP (a cellobiose phosphorylase from Cellulomonas uda), and CcCdP (a cellodextrin phosphorylase from Clostridium cellulosi) were shown to be able to promote plant growth. The current study pointed to an approach to make use of CCR for production of the value-added COS. KEY POINTS: • Sequential use of cellulase and phosphorylases effectively generated cello-oligosaccharides from corncob residue. • Cello-oligosaccharides patterns varied in accordance to cellobiose/cellodextrin phosphorylases. • Spraying cello-oligosaccharides promoted tomato growth.

Ultrafast and highly efficient Cd(II) and Pb(II) removal by magnetic adsorbents derived from gypsum and corncob: Performances and mechanisms.

The utilization of gypsum and biomass in environmental remediation has become a novel approach to promote waste recycling. Generally, raw waste materials exhibit limited adsorption capacity for heavy metal ions (HMIs) and often result in poor solid-liquid separation. In this study, through co-pyrolysis with corncob waste, titanium gypsum (TiG) was transformed into magnetic adsorbents (GCx, where x denotes the proportion of corncob in the gypsum-corncob mixture) for the removal of Cd(II) and Pb(II). GC10, the optimal adsorbent, which was composed primarily of anhydrite, calcium sulfide, and magnetic Fe3O4, exhibited significantly faster adsorption kinetics (rate constant k1 was 218 times and 9 times of raw TiG for Cd(II) and Pb(II)) and higher adsorption capacity (Qe exceeded 200 mg/g for Cd(II) and 400 mg/g for Pb(II)) than raw TiG and previous adsorbents. Cd(II) removal was more profoundly inhibited in a Cd(II) + Pb(II) binary system, suggesting that GC10 showed better selectivity for Pb(II). Moreover, GC10 could be easily separated from purified water for further recovery, due to its high saturation magnetization value (6.3 emu/g). The superior removal capabilities of GC10 were due to adsorption and surface precipitation of metal sulfides and metal sulfates on the adsorbent surface. Overall, these waste-derived magnetic adsorbents provide a novel and sustainable approach to waste recycling and the deep purification of multiple HMIs.

Bedding as a variable affecting fasting blood glucose and vascular physiology in mice.

Rodent husbandry requires careful consideration of environmental factors that may impact colony performance and subsequent physiological studies. Of note, recent reports have suggested corncob bedding may affect a broad range of organ systems. As corncob bedding may contain digestible hemicelluloses, trace sugars, and fiber, we hypothesized that corncob bedding impacts overnight fasting blood glucose and murine vascular function. Here, we compared mice housed on corncob bedding, which were then fasted overnight on either corncob or ALPHA-dri bedding, a virgin paper pulp cellulose alternative. Male and female mice were used from two noninduced, endothelial-specific conditional knockout strains [Cadherin 5-cre/ERT2, floxed hemoglobin-α1 (Hba1fl/fl) or Cadherin 5-cre/ERT2, floxed cytochrome-B5 reductase 3 (CyB5R3fl/fl)] on a C57BL/6J genetic background. After fasting overnight, initial fasting blood glucose was measured, and mice were anesthetized with isoflurane for measurement of blood perfusion via laser speckle contrast analysis using a PeriMed PeriCam PSI NR system. After a 15-min equilibration, the mice were injected intraperitoneally with the α1-adrenergic receptor agonist, phenylephrine (5 mg/kg), or saline, and monitored for changes in blood perfusion. After a 15-min response period, blood glucose was remeasured postprocedure. In both strains, mice fasted on corncob bedding had higher blood glucose than the pulp cellulose group. In the CyB5R3fl/fl strain, mice housed on corncob bedding displayed a significant reduction in phenylephrine-mediated change in perfusion. In the Hba1fl/fl strain, phenylephrine-induced change in perfusion was not different in the corncob group. This work suggests that corncob bedding, in part due to its ingestion by mice, could impact vascular measurements and fasting blood glucose. To promote scientific rigor and improve reproducibility, bedding type should be routinely included in published methods.NEW & NOTEWORTHY This study demonstrates real-time measurement of changes in perfusion to pharmacological treatment using laser speckle contrast analysis. Furthermore, this investigation revealed that fasting mice overnight on corncob bedding has differential effects on vascular function and that there was increased fasting blood glucose in mice fasted on corncob bedding compared with paper pulp cellulose bedding. This highlights the impact that bedding type can have on outcomes in vascular and metabolic research and reinforces the need for thorough and robust reporting of animal husbandry practices.

Development of engineered Candida tropicalis strain for efficient corncob-based xylitol-ethanol biorefinery.

BACKGROUND: Xylitol has a wide range of applications in the pharmaceuticals, cosmetic, food and beverage industry. Microbial xylitol production reduces the risk of contamination and is considered as environment friendly and sustainable compared to the chemical method. In this study, random mutagenesis and genetic engineering approaches were employed to develop Candida tropicalis strains with reduced xylitol dehydrogenase (XDH) activity to eliminate co-substrate requirement for corn cob-based xylitol-ethanol biorefinery. RESULTS: The results suggest that when pure xylose (10% w/v) was fermented in bioreactor, the Ethyl methane sulfonate (EMS) mutated strain (C. tropicalis K2M) showed 9.2% and XYL2 heterozygous (XYL2/xyl2Δ::FRT) strain (C. tropicalis K21D) showed 16% improvement in xylitol production compared to parental strain (C. tropicalis K2). Furthermore, 1.5-fold improvement (88.62 g/L to 132 g/L) in xylitol production was achieved by C. tropicalis K21D after Response Surface Methodology (RSM) and one factor at a time (OFAT) applied for media component optimization. Finally, corncob hydrolysate was tested for xylitol production in biorefinery mode, which leads to the production of 32.6 g/L xylitol from hemicellulosic fraction, 32.0 g/L ethanol from cellulosic fraction and 13.0 g/L animal feed. CONCLUSIONS: This work, for the first time, illustrates the potential of C. tropicalis K21D as a microbial cell factory for efficient production of xylitol and ethanol via an integrated biorefinery framework by utilising lignocellulosic biomass with minimum waste generation.

Fast and Selective Degradation of Biomass for Xylose, Glucose and Lignin under Mild Conditions.

The conversion of lignocellulose into valuable chemicals has been recognized as the key technology in green chemistry. However, selective degradation of hemicellulose and cellulose with the production of lignin is still a challenge. Therefore, a two-step process has been developed to degrade corncob into xylose and glucose under mild conditions. At first, the corncob was treated with the lower concentration of zinc chloride aqueous solution (30-55 w%) at 95 °C with a short reaction time (8-12 min) and 30.4 w% (selectivity = 89%) of xylose obtained with a solid residue of the composite of cellulose and lignin. Next, the solid residue was treated with a high concentration of zinc chloride aqueous solution (65-85 w%) at 95 °C for about 10 min, and 29.4 w% (selectivity = 92%) of glucose can be obtained. Combining the two steps, the total yield of xylose is 97%, while glucose is 95%. In addition, high pure lignin can be obtained simultaneously, which was confirmed using HSQC studies. Furthermore, for the solid residue of the first-step reaction, a ternary deep eutectic solvent (DES) (choline chloride/oxalic acid/1,4-butanediol, ChCl/OA/BD) has been used to separate the cellulose and lignin efficiently, and high-quality cellulose (Re-C) and lignin (Re-L) were obtained. Furthermore, it provides a simple method to disassemble the lignocellulose for monosaccharides, lignin, and cellulose.

Modulating the Graphitic Domains and Pore Structure of Corncob-Derived Hard Carbons by Pyrolysis to Improve Sodium Storage.

Biomass-derived hard carbon materials are considered as the most promising anode materials for sodium-ion batteries (SIBs) due to their abundant sources, environmental friendliness, and excellent electrochemical performance. Although much research exists on the effect of pyrolysis temperature on the microstructure of hard carbon materials, there are few reports that focus on the development of pore structure during the pyrolysis process. In this study, corncob is used as the raw material to synthesize hard carbon at a pyrolysis temperature of 1000~1600 °C, and their interrelationationship between pyrolysis temperature, microstructure and sodium storage properties are systematically studied. With the pyrolysis temperature increasing from 1000 °C to 1400 °C, the number of graphite microcrystal layers increases, the long-range order degree rises, and the pore structure shows a larger size and wide distribution. The specific capacity, the initial coulomb efficiency, and the rate performance of hard carbon materials improve simultaneously. However, as the pyrolysis temperature rises further to 1600 °C, the graphite-like layer begins to curl, and the number of graphite microcrystal layers reduces. In return, the electrochemical performance of the hard carbon material decreases. This model of pyrolysis temperatures-microstructure-sodium storage properties will provide a theoretical basis for the research and application of biomass hard carbon materials in SIBs.

Adsorption Performance of Methylene Blue by KOH/FeCl3 Modified Biochar/Alginate Composite Beads Derived from Agricultural Waste.

In this study, high-performance modified biochar/alginate composite bead (MCB/ALG) adsorbents were prepared from recycled agricultural waste corncobs by a high-temperature pyrolysis and KOH/FeCl3 activation process. The prepared MCB/ALG beads were tested for the adsorption of methylene blue (MB) dye from wastewater. A variety of analytical methods, such as SEM, BET, FTIR and XRD, were used to investigate the structure and properties of the as-prepared adsorbents. The effects of solution pH, time, initial MB concentration and adsorption temperature on the adsorption performance of MCB/ALG beads were discussed in detail. The results showed that the adsorption equilibrium of MB dye was consistent with the Langmuir isothermal model and the pseudo-second-order kinetic model. The maximum adsorption capacity of MCB/ALG-1 could reach 1373.49 mg/g at 303 K. The thermodynamic studies implied endothermic and spontaneous properties of the adsorption system. This high adsorption performance of MCB/ALG was mainly attributed to pore filling, hydrogen bonding and electrostatic interactions. The regeneration experiments showed that the removal rate of MB could still reach 85% even after five cycles of experiments, indicating that MCB/ALG had good reusability and stability. These results suggested that a win-win strategy of applying agricultural waste to water remediation was feasible.

Hydrogen Sulfide Removal via Sorption Process on Activated Carbon-Metal Oxide Composites Derived from Different Biomass Sources.

Biomass exploitation is a global trend due to the circular economy and the environmentally friendly spirit. Numerous applications are now based on the use of biomass-derived products. Hydrogen sulfide (H2S) is a highly toxic and environmentally hazardous gas which is emitted from various processes. Thus, the efficient removal of this toxic hazardous gas following cost-effective processes is an essential requirement. In this study, we present the synthesis and characterization of biomass-derived activated carbon/zinc oxide (ZnO@AC) composites from different biomass sources as potential candidates for H2S sorption. The synthesis involved a facile method for activated carbon production via pyrolysis and chemical activation of biomass precursors (spent coffee, Aloe-Vera waste leaves, and corncob). Activated carbon production was followed by the incorporation of zinc oxide nanoparticles into the porous carbon matrix using a simple melt impregnation method. The synthesized ZnO@AC composites were characterized using X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and nitrogen porosimetry. The H2S removal performance of the ZnO@AC composites was evaluated through sorption experiments using a handmade apparatus. Our findings demonstrate that the Aloe-Vera-, spent coffee-, and corncob-derived composites exhibit superior H2S sorption capacity up to 106 mgH2S/gads., 66 mgH2S/gads., and 47 mgH2S/gads., respectively.

Food-grade xylitol production from corncob biomass with acute oral toxicity studies.

Xylitol, a sugar substitute, is widely used in various food formulations and finds a steady global market. In this study, xylitol crystals were produced from corncob by fermentation (as an alternative to the chemical catalytic process) by a GRAS yeast Pichia caribbica MTCC 5703 and characterized in detail for their purity and presence of any possible contaminant that may adversely affect mammalian cell growth and proliferation. The acute and chronic oral toxicity trials demonstrated no gross pathological changes with average weekly weight gain in female Wistar rats at high xylitol loading (LD50 > 10,000 mg/kg body weight). The clinical chemistry analysis supported the evidence of no dose-dependent effect by analyzing blood biochemical parameters. The finding suggests the possible application of the crystals (> 98% purity) as a food-grade ingredient for commercial manufacture pending human trials.

Structural characterization of a novel polysaccharide from sweet corncob that inhibits glycosylase in STZ-induced diabetic rats : Structural characterization of a novel polysaccharide.

In the current study, we extracted a polysaccharide from sweet corncob and evaluated its hypoglycemic function. After collection in water, alcohol precipitation, and purification by DEAE-52 and Sephadex G-100 columns, we obtained a polysaccharide (SCP50) that was composed primarily of mannose and glucose (9.73:190.27), with a molecular weight of 9280.33 Da. We demonstrated that SCP50 exhibited significant inhibition of α-glucosidase activity, with an IC50 of 4.866 mg/mL, Km of 1.297 × 10-3, and Vmax of 0.076 mol/L·min-1 in vitro. We also observed that SCP50 markedly attenuated disaccharidase (maltase, sucrase, and lactase) activity in a rat model of T2DM. We conclude that SCP50 exerts a hypoglycemic effect via inhibition of intestinal glycosylase. These results thus provide new insight into the hypoglycemic action underlying sweet corncob polysaccharide's effects.

A sustainable, low-cost carbonaceous hydrochar adsorbent for methylene blue adsorption derived from corncobs.

In this study, activated carbon from corncobs was successfully synthesized by hydrothermal carbonization and hydrochemical activation at low temperatures, followed by pyrolysis. A developed method of hydrochemical activation of hydrochar that uses only small amounts of chemicals is a promising approach. After activation, the activator residues in the hydrothermal product can constantly act as a chemical activator during pyrolysis to form corncob-activated carbon (AHC-KOH), which had specific surface area of 965.028 m2/g and oxygenated functional groups of 0.3780 mmol/g, 31.67 and 4 times, respectively, of those of the inactivated sample. AHC-KOH was used to study the adsorption characteristics of methylene blue (MB). The MB adsorption efficiency of AHC-KOH was the highest at 489.560 mg/g, which was considerably higher than that of activated carbons produced from other biomasses. The isotherm equilibrium and adsorbent kinetics parameters of MB adsorption on AHC-KOH were also determined using the Langmuir isotherm model (R2 = 0.99) and pseudo-second-order kinetic model (R2 > 0.99). Thus, the results indicate that an inexpensive adsorbent produced from corncobs using the above method is a promising material for wastewater treatment.

Denitrification performance and characteristics of untreated corncob for enhanced nitrogen removal of municipal sewage with low C/N ratio.

Unpretreated corncob was applied in denitrification bio-filter (DNBF) and anoxic tank of AAO system, respectively, to treat sewage with low C/N ratio, and both two approaches achieved good denitrification performance. Although shorter HRT could effectively decrease effluent chroma and COD of corncob-DNBF, nitrogen removal efficiency declined unexpectedly. Higher internal reflux ratio was beneficial for corncob-AAO without damage to anoxic environment for denitrification, while there was no risk of effluent chroma and excessive COD. Different supplement modes could realize same denitrification effect with distinct advantages, which were higher specific denitrification rate and biomass amount, respectively. The latter mode, applying corncob at secondary treatment, was preferable for its operational stability and convenience. Stoichiometry analysis indicated the unit COD demand of AAO decreased from 5.70 to 5.04 g COD/g N after adding corncob, and the oxygen demand (or energy consumption of aeration) decreased as well. The dominant substrates decomposer in corncob-AAO altered to Kouleothrix (affiliated to phylum Chloroflexi), and the main denitrifying bacteria were unclassified_f__Methylophilaceae and Azospira. Accordingly, functional enzymes for degrading glucan, xylan and lignin and processing denitrification showed satisfying abundance in the integrated system, especially in the newly formed biofilm.

Biosurfactants produced from corncob: a bibliometric perspective of a renewable and promising substrate.

The reuse of agro-industrial waste has been a recurring issue since the 20th century. With a composition rich in carbohydrates and because of the massive amount of residue produced daily all over the world, corncob became a low-cost and suitable substrate to produce high added-value compounds. Biosurfactants are bioproducts of versatile applications due to their chemical structure with hydrophilic and hydrophobic regions. The current work performed a bibliometric analysis to identify research related to the synthesis of biosurfactants using corncob as substrate. Despite the high availability of corncobs, only nine articles were found in Scopus and Web of Science using different pretreatment processes and microorganisms. After an initial screening, data regarding research organizations, scientific journals, citations, countries, institutions, and keywords were analyzed. Results indicated that corncobs were also used to produce enzymes, adsorbents, activated carbon, and furfural. The presented evaluation updated the status of art, identifying a serious need for more research, especially because of corncob's high potential to provide fermentable sugars and the wide range of variables influencing fermentation processes that still need to be studied. A future association of this low-cost substrate with other methods can result in a promising scenario for technology transference.

High Efficiency Adsorption Removal of Arsenilic Acid and Arsenate(V) by Iron-Modified Corncob Biochar.

It is crucial that a highly effective adsorbent can be used to simultaneously remove the composite pollution including both inorganic and organic arsenic from wastewater. In this work, the iron modified corncob biochar (MCCB), prepared via the co-precipitation of ferric chloride hexahydrate (FeCl3⋅6H2O) with sodium hydroxide (NaOH) on corncob biochar, was studied for the high efficiency removal of arsenilic acid (ASA) and arsenate [As(V)] in wastewater. X-ray diffraction, scanning electron microscopy, and fourier transform infrared spectroscopy were carried out to characterize the MCCB. At pH of 4.0-5.0, initial concentration of 10 mg/L ASA and 1 mg/L As(V), adsorbent dose of 0.4 g/L, the maximum adsorption capacities of ASA and As(V) were 49.20 and 4.89 mg/g, respectively. The adsorption performance of MCCB for ASA and As(V) was fitted well to the pseudo-second-order kinetic model. Results from this study indicate the promise of MCCB as an efficient, low-cost and environmentally friendly adsorbent for composite arsenic pollution.

Improved enzyme production on corncob hydrolysate by a xylose-evolved Pichia pastoris cell factory.

The global shift from the usage of crude oil in bio-production is receiving much attention owing to environmental concern associated with fossil fuel. Lignocellulosic biomass (LB) is a good carbon candidate for bio-production because it is environmental-friendly. Corncob being one of such LB is rich in glucose and xylose, which can be utilized for bio-production. We co-utilize these sugars for the production of enzymes from Pichia pastoris GS115 (Wild Type: WT). Glucose utilization was efficient from synthetic and real hydrolysate but xylose utilization was very low, hence, the need for optimization. Mutants were selected upon Adaptive Laboratory Evolution to efficiently utilize xylose. As expected, all the mutants examined showed improved xylose utilization but surprisingly, there was only 1.8 g/l residual xylose in the 50th generation (GS50). The 30th evolutionary generation (GS30) compared well with the WT by completely utilizing the glucose and also accumulated 48 OD600 cell biomass, which is the highest among all the strains evaluated. More importantly, GS30 secreted 72.6 U/ml and 45.1 U/ml ß-galactosidase and ß-mannanase on hydrolysate respectively, which are higher than the titre for the WT. Conclusively, this study demonstrated the efficacy of corn corncob hydrolysate in biomanufacturing and gives insight for the optimization study.

Comparison of performances of different fungal laccases in delignification and detoxification of alkali-pretreated corncob for bioethanol production.

The performance of the alkaline fungal laccase PIE5 (pH 8.5) in the delignification and detoxification of alkali-pretreated corncob to produce bioethanol was evaluated and compared with that of the neutral counterpart (rLcc9, 6.5), with the acidic laccase rLacA (4.0) was used as an independent control. Treatment with the three laccases facilitated bioethanol production compared with their respective controls. The lignin contents of alkali-pretreated corncob reduced from 4.06%, 5.06%, and 7.80% to 3.44%, 3.95%, and 5.03%, after PIE5, rLcc9, and rLacA treatment, respectively. However, the performances of the laccases were in the order rLacA > rLcc9 > PIE5 in terms of decreasing total phenol concentration (0.18, 0.36, and 0.67 g/l), boosting ethanol concentration (8.02, 7.51, and 7.31 g/l), and volumetric ethanol productivity (1.34, 0.94, and 0.91 g/l hr), and shortening overall fermentation time. Our results would inform future attempts to improve laccases for ethanol production. Furthermore, based on our data and the fact that additional procedures, such as pH adjustment, are needed during neutral/alkaline fungal laccase treatment, we suggest acidic fungal laccases may be a better choice than neutral/alkaline fungal laccases in bioethanol production.

Purified anthocyanins from Zea mays L. cob ameliorates chronic liver injury in mice via modulating of oxidative stress and apoptosis.

BACKGROUND: Purple corn (Zea mays L.) is one of the main economic crops in China and has been used in the treatment of cystitis, urinary infections and obesity. However, purple corncobs, the by-product remaining after processing and having an intense purple-black color, are normally disposed of as waste or used as animal feed. Therefore, to further expand the medicinal value of purple corncob, its content was analyzed and, after purification, the effect and mechanism of purified purple corncob anthocyanins (PPCCA) on CCl4 -induced chronic liver injury in mice were investigated. RESULTS: It was observed that the total anthocyanin content (TAC) from PPCCA (317.51 ± 9.30 mg cyanidin 3-O-glucoside (C-3-G) g-1 dry weight) was significantly higher than that from the purified purple corn seed anthocyanin (266.73 ± 3.67 mg C-3-G g-1 dry weight), of which C-3-G accounted for 90.6% and 90.4% of the TAC, respectively. Furthermore, compared with the CCl4 group, PPCCA treatment significantly reduced liver index, serum total bilirubin, alanine transaminase, aspartate transaminase and liver malondialdehyde levels, but increased liver superoxide dismutase activity. The pathological changes were also improved, such as more regular arrangement of hepatocytes, less swelling, and fewer vacuoles and apoptotic cells. Additionally, mechanistic studies showed that PPCCA downregulated the expression of Caspase-3, Bax and cytochrome P450 2E1 proteins in the liver and upregulated the expression of Bcl-2. CONCLUSION: These results demonstrated that PPCCA could ameliorate CCl4 -induced chronic liver injury by regulating oxidative stress and hepatocyte apoptosis pathways. © 2021 Society of Chemical Industry.

Consolidated bioprocessing performance of a two-species microbial consortium for butanol production from lignocellulosic biomass.

Consolidated bioprocessing (CBP) by using microbial consortium was considered as a promising approach to achieve direct biofuel production from lignocellulose. In this study, the interaction mechanism of microbial consortium consisting of Thermoanaerobacterium thermosaccharolyticum M5 and Clostridium acetobutylicum NJ4 was analyzed, which could achieve efficient butanol production from xylan through CBP. Strain M5 possesses efficient xylan degradation capability, as 19.73 g/L of xylose was accumulated within 50 hr. The efficient xylose utilization capability of partner strain NJ4 could relieve the substrate inhibition to hydrolytic enzymes of xylanase and xylosidase secreted by strain M5. In addition, the earlier solventogenesis of strain NJ4 was observed due to the existence of butyrate generated by strain M5. The mutual interaction of these two strains finally gave 13.28 g/L of butanol from 70 g/L of xylan after process optimization, representing a relatively high butanol production from hemicellulose. Moreover, 7.61 g/L of butanol was generated from untreated corncob via CBP. This successfully constructed microbial consortium exhibits efficient cooperation performance on butanol production from lignocellulose, which could provide a platform for the emerging butanol production from lignocellulose.

Study on the Adsorption of CuFe2O4-Loaded Corncob Biochar for Pb(II).

A series of the magnetic CuFe2O4-loaded corncob biochar (CuFe2O4@CCBC) materials was obtained by combining the two-step impregnation of the corncob biochar with the pyrolysis of oxalate. CuFe2O4@CCBC and the pristine corncob biochar (CCBC) were characterized using XRD, SEM, VSM, BET, as well as pHZPC measurements. The results revealed that CuFe2O4 had a face-centered cubic crystalline phase and was homogeneously coated on the surface of CCBC. The as-prepared CuFe2O4@CCBC(5%) demonstrated a specific surface area of 74.98 m2·g-1, saturation magnetization of 5.75 emu·g-1 and pHZPC of 7.0. The adsorption dynamics and thermodynamic behavior of Pb(II) on CuFe2O4@CCBC and CCBC were investigated. The findings indicated that the pseudo-second kinetic and Langmuir equations suitably fitted the Pb(II) adsorption by CuFe2O4@CCBC or CCBC. At 30 °C and pH = 5.0, CuFe2O4@CCBC(5%) displayed an excellent performance in terms of the process rate and adsorption capacity towards Pb(II), for which the theoretical rate constant (k2) and maximum adsorption capacity (qm) were 7.68 × 10-3 g·mg-1··min-1 and 132.10 mg·g-1 separately, which were obviously higher than those of CCBC (4.38 × 10-3 g·mg-1·min-1 and 15.66 mg·g-1). The thermodynamic analyses exhibited that the adsorption reaction of the materials was endothermic and entropy-driven. The XPS and FTIR results revealed that the removal mechanism could be mainly attributed to the replacement of Pb2+ for H+ in Fe/Cu-OH and -COOH to form the inner surface complexes. Overall, the magnetic CuFe2O4-loaded biochar presents a high potential for use as an eco-friendly adsorbent to eliminate the heavy metals from the wastewater streams.