Waste Wheat Research Articles

Cellulose aerogels functionalized with polypyrrole and silver nanoparticles: In-situ synthesis, characterization and antibacterial activity

Green porous and lightweight cellulose aerogels have been considered as promising candidates to substitute some petrochemical host materials to support various nanomaterials. In this work, waste wheat straw was collected as feedstock to fabricate cellulose hydrogels, and a green inexpensive NaOH/polyethylene glycol solution was used as cellulose solvent. Prior to freeze-drying treatment, the cellulose hydrogels were integrated with polypyrrole and silver nanoparticles by easily-operated in-situ oxidative polymerization of pyrrole using silver ions as oxidizing agent. The tri-component hybrid aerogels were characterized by scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectroscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and X-ray diffraction. Moreover, the antibacterial activity of the hybrid aerogels against Escherichia coli (Gram-negative), Staphylococcus aureus (Gram-positive) and Listeria monocytogenes (intracellular bacteria) was qualitatively and quantitatively investigated by parallel streak method and determination of minimal inhibitory concentration, respectively. This work provides an example of combining cellulose aerogels with nanomaterials, and helps to develop novel forms of cellulose-based functional materials.

The effect of support particle type on thermophilic hydrogen production by immobilized batch dark fermentation

The objective of the study was to select microorganism support particle to enhance hydrogen production in an immobilized system by dark fermentation. Stainless steel scrubber, volcanic stone, tulle, polyester fiber, loofah sponge, plastic bath sponge, sea sponge and aquarium biological sponges were used as support materials to investigate hydrogen production potentials of these particles. Waste wheat was the substrate and it was hydrolyzed in diluted sulfuric acid at high temperature to obtain sugar solution. Heat and acid pretreatment method was applied to anaerobic sludge to eliminate methanogens and to select spore forming hydrogen producing bacteria like Clostridium sp. Experiments were conducted at different initial total sugar concentrations TS0 = 13 ± 1 g/L, 17 ± 1 g/L, 27 ± 3 g/L under thermophilic conditions (55 °C) for all particle types. The highest hydrogen yield (YH2 = 1.96 mol H2/mol glucose) and maximum hydrogen production rate (HPR = 7.39 ml H2/h) were obtained with polyester fiber particles at TS0 = 13 ± 1 g/L. The particle size of polyester fiber was varied between Dp = 0.5–3 cm at TS0 = 13 ± 1 g/L. The highest production yield of 1.96 mol H2/mol glucose was obtained with particle size of Dp = 1.5 cm. The results indicated that polyester fiber can be used as microorganism support particle for hydrogen production in immobilized bioprocesses.

English

Biodegradation with heterogeneous catalysts were successfully carried out in the production of biogas from wheat wastes, rice husk and spent grains. Five digesters were charged with spent grains/clay soil, spent grains/lime stone, rice husk/clay soil, rice husk/lime stone and wheat wastes/potash, respectively. Clay soil, limestone and potash were used as catalysts for optimizing and to speed up the chemical reactions in the digestions. The total viable count, total mold count, structural absorbance and transmittance, and micrograph of the wastes were carried on the waste samples. The digestions were carried out for a period of sixty (60) days. Results showed that spent grain/clay soil set-up produced combustible biogas on the 4th day with total cumulative biogas of 69.3 L, followed by wheat wastes/potash which produced combustible biogas on the 34th day with total cumulative biogas of 178.5 L. Proximate analysis was performed on the gas samples, showing the presence nitrogen, phosphorous and potassium (NPK). Characterizations using combustion analyzer showed that methane content of Exp.A and Exp.E were 75.6 and 81.7%. Key words: Optimizing, catalyst, combustible, transmittance, micrograph.

Selection of microorganism immobilization particle for dark fermentative biohydrogen production by repeated batch operation

The objective of this study was to evaluate the hydrogen production potentials of different microbial support particles namely; plastic scouring sponge pad, plastic nylon sponge, black porous sponge, plastic scouring sponge pad with metal mesh, plastic nylon sponge with metal mesh to be used in an immobilized bioprocess system. The experiments were conducted in repeated batch mode at retention times between 1 and 5 day. The substrate was waste wheat which was sieved down to 70 μm size (less than 200 mesh) first and then, hydrolyzed by using H2SO4 at pH = 2 and 90 °C in an autoclave for 15 min. The sugar solution obtained from hydrolysis of waste wheat was used as substrate after neutralization and nutrient addition. Hydrogen production potentials of different particles were evaluated through cumulative hydrogen volume and hydrogen production yield. Control experiments without particles were conducted in parallel to the experiments with particles to evaluate the effect of immobilization on production. The yield of production increased with decreasing retention time from 5 day to 1 day for all particles. The highest yield was achieved as 2.1 mol/mol glucose with metal mesh covered plastic scouring sponge pad at 1 day retention time repeated batch operation.

Cellulose aerogels from cellulose–NaOH/PEG solution and comparison with different cellulose contents

A green mild NaOH/polyethylene glycol solution was employed to dissolve the cellulose extracted from waste wheat straw. Subsequently combined with the freezing−thawing treatment, regeneration process and freeze drying, the cellulose aerogels with different cellulose contents were fabricated at mass ratios of 1∶100, 3∶100, 5∶100 and 7∶100 cellulose to the solution. Moreover, the influences of cellulose contents on the morphologies, crystal structures, crystallinity indexes, thermal stabilities and pore characteristic parameters of the aerogels were investigated by scanning electron microscope, X-ray diffraction, thermogravimetric analysis and nitrogen adsorption. Meanwhile, the oil adsorption properties of the aerogels with different cellulose contents were also surveyed; besides, for improving lipophilicity, the hydrophobic modifications of trimethylchlorosilane for the aerogels were carried out before the adsorption tests.

Simultaneous saccharification and ethanol fermentation of waste wheat–rye bread at very high solids loading: Effect of enzymatic liquefaction conditions

The aim of this research was to investigate the ethanol fermentation process course and yield from waste wheat–rye bread in the simultaneous saccharification and fermentation (SSF) conditions at high solids loading (300gkg−1). Moreover the enzymatic liquefaction conditions were modified on the basis of thermal properties of starch and compared to the temperature optimal for α-amylase activity (85°C). The liquefaction of raw material at modified conditions decreased the hydrolysis efficiency in comparison to hydrolysis at 85°C. The course and ethanol yield of the SSF process in the optimized conditions of liquefaction was comparable or even higher in comparison to standard conditions. The best results were obtained when starch was liquefied at the final temperature of gelatinization (59°C) resulting in final ethanol concentration of 128.01gL−1 yielding 425.04gkg−1 of dry matter and 95.93% practical yield (416.09gkg−1 and 93.91% for liquefaction at 85°C).

Low-Cost Biodegradation and Detoxification of Textile Azo Dye C.I. Reactive Blue 172 byProvidencia rettgeriStrain HSL1

Present study focuses on exploitation of agricultural waste wheat bran (WB) as growth medium for degradation of textile azo dye C.I. Reactive Blue 172 (RB 172) using a single bacteriumP. rettgeristrain HSL1 (GenBank accession numberJX853768.1). The bacterium was found to completely decolorize 50 mg L−1of dye RB 172 within 20 h at 30 ± 0.2°C under microaerophilic incubation conditions. Additionally, significant reduction in COD (85%) and TOC (52%) contents of dye decolorized medium was observed which suggested its mineralization. Induction in the activities of azoreductase (159%) and NADH-DCIP reductase (88%) provided an evidence for reductive cleavage of dye RB 172. The HPLC, FTIR, and GC-MS analysis of decolorized products confirmed the degradation of dye into various metabolites. The proposed metabolic pathway for biodegradation of RB 172 has been elucidated which showed the formation of 2 intermediate metabolites, namely, 4-(ethenylsulfonyl) aniline and 1-amino-1-(4-aminophenyl) propan-2-one. The acute and phytotoxicity evaluation of degraded metabolites suggests that bacterial strain favors the detoxification of dye RB 172. Thus, WB could be utilized as a low-cost growth medium for the enrichment of bacteria and their further use for biodegradation of azo dyes and its derivatives containing wastes into nontoxic form.

Autohydrolysis pretreatment of waste wheat straw for cellulosic ethanol production in a co-located straw pulp mill.

Waste wheat straw (WWS) is the waste product from feedstock preparation process in a straw pulp mill. It has a significant annual production rate and no commercial value has been explored on this material. In this study, waste wheat straw was pretreated using an autohydrolysis process followed by mechanical refining, and the pretreated materials were further enzymatically hydrolyzed to evaluate the total sugar recovery for bioethanol production. Results show that autohydrolysis at 170 °C for 40 min followed by 6000 revolution PFI refining provided the best result in this study, where a total sugar recovery (total sugars in autohydrolysis filtrate and enzymatic hydrolyzate over total carbohydrates on raw WWS) of 70 % at 4 filter paper unit per oven dry gram (FPU/OD g) substrate enzyme charge could be obtained. The economic evaluation of this biorefinery process indicates that cellulosic ethanol production from autohydrolysis of WWS is a very profitable business, with 28.4 % of internal rate of return can be achieved based on current ethanol wholesale price in China.

Enhanced antioxidant properties as a function of selenium uptake by edible mushrooms cultivated on selenium-accumulated waste post-harvest wheat and paddy residues

Background Majority of the post-harvest agri-residues from agricultural activity in Punjab, India, is burnt in the field resulting in the loss of soil fertility and release of large amounts of air pollutants. In an effort to reutilize the selenium-accumulated waste wheat and paddy straw from seleniferous region of Punjab, two varieties of edible mushrooms, Pleurotus sajor-kaju and Volvariella volvacea, were cultivated on Se-rich wheat and paddy straw, respectively.

Production and partial characterization of serine and metallo peptidases secreted by Aspergillus fumigatus Fresenius in submerged and solid state fermentation.

Enzyme production varies in different fermentation systems. Enzyme expression in different fermentation systems yields important information for improving our understanding of enzymatic production induction. Comparative studies between solid-state fermentation (SSF) using agro-industrial waste wheat bran and submerged fermentation (SmF) using synthetic media were carried out to determinate the best parameters for peptidase production by the fungus Aspergillus fumigatus Fresen. Variables tested include: the concentration of carbon and protein nitrogen sources, the size of the inoculum, the pH of the media, temperature, and the length of the fermentation process. The best peptidase production during SSF was obtained after 96 hours using wheat bran at 30 °C with an inoculum of 1 × 106 spores and yielded 1500 active units (U/mL). The best peptidase production using SmF was obtained after periods of 72 and 96 hours of fermentation in media containing 0.5% and 0.25% of casein, respectively, at a pH of 6.0 and at 30 °C and yielded 40 U/mL. We also found examples of catabolite repression of peptidase production under SmF conditions. Biochemical characterization of the peptidases produced by both fermentative processes showed optimum activity at pH 8.0 and 50 °C, and also showed that their proteolytic activity is modulated by surfactants. The enzymatic inhibition profile using phenylmethylsulfonyl fluoride (PMSF) in SmF and SSF indicated that both fermentative processes produced a serine peptidase. Additionally, the inhibitory effect of the ethylene-diaminetetraacetic acid (EDTA) chelating agent on the peptidase produced by SmF indicated that this fermentative process also produced a metallopeptidase.

A Biosecure Composting System for <i>Tilletia controversa Kühn</i>-Infected Wheat Waste

Tilletia controversa Kühn (TCK) has strong infectivity and viability and may cause great cut hazard to wheat and other crops. Composting treatment of TCK-infected wheat waste may be an effective method to eliminate the further contamination. This study applied microbial fermentation composting technique using mixed crop straws and manure to establish a bio-friendly composting method. The change of physicochemical properties of the compost was monitored regularly to detect the time course of TCK degradation and confirm the inactivation of TCK germination activity. The results of regular sampling indicate that the germination rate of TCK declines with the composting progress, and composting ten days under the condition of 50℃ to 60℃ completely inactivates the germination ability of TCK. Thus the present study provides a bio-friendly composting method for degrading TCK-infected wheat crops under TCK outbreak.

Hydrogen gas production from acid hydrolyzed wheat starch by combined dark and photo-fermentation with periodic feeding

Hydrogen gas production from acid hydrolyzed waste wheat starch by combined dark and photo-fermentation was investigated in continuous mode with periodic feeding and effluent removal. A mixture of heat treated anaerobic sludge and Rhodobacter sphaeroides (NRRL-B 1727) were used as the seed culture for dark and light fermentations, respectively with biomass ratio of Rhodobacter/sludge = 3. Hydraulic residence time (HRT) was changed between 1 and 8 days by adjusting the feeding periods. Ground waste wheat was acid hydrolyzed at pH = 3 and 121 °C for 30 min using an autoclave and the resulting sugar solution was used as the substrate for combined fermentation after pH adjustment and nutrient addition. The highest daily hydrogen gas production (41 ml d −1), hydrogen yield (470 ml g −1 total sugar = 3.4 mol H 2 mol −1glucose), volumetric and specific hydrogen production rates were obtained at the HRT of 8 days. The highest biomass and the lowest total volatile fatty acids (TVFA) concentrations were also realized at HRT = 8 days indicating VFA fermentation by Rhodobacter sp. at high HRTs. The lowest total sugar loading rate of 0.625 g L −1 d −1 resulted in the highest hydrogen yield and formation rate. Hydrogen gas production by combined fermentation with periodic feeding was proven to be an effective method resulting in high hydrogen yields at long HRTs.

Dark fermentative bio-hydrogen production from waste wheat starch using co-culture with periodic feeding: Effects of substrate loading rate

Dark fermentation experiments were performed for bio-hydrogen production from ground wheat starch solution (10 ± 1 g l −1) using periodic feeding and effluent removal. A mixed culture of Clostridium butyricum-NRRL 1024 and Clostridium pasteurianum-NRRL B-598 were used with an initial biomass ratio of 1/1.Effects of wheat starch loading rate on the rate and yield of bio-hydrogen formation were investigated. Substrate loading rate was varied between 0.54 and 5.52 g d −1 (HRT = 6–60 h). The highest hydrogen formation rate (280 ml d −1), volumetric hydrogen formation rate (1857 ml H 2 l −1 d −1) and volatile fatty acids (VFAs) concentration were obtained with a substrate loading rate of 5.52 g d −1 (HRT = 6 h). The highest hydrogen yield (109 ml H 2 g TS −1) was obtained with a substrate loading rate of 1.38 g d −1.

Refining Response of Fibre Materials with Medium Consistency Refiners

Several kinds of fibre materials including waste paper, wheat straw, bamboo and hardwood pulp were refined by using medium consistency refiner (MC refiner) at pulp consistency of 6-10%, and fibre fractions classification and length distribution after refining, paper physical properties and specific energy consumption during refining were compared with the refining process by using traditional low consistency refiner (LC refiner) at pulp consistency of 3-4%. The objective of this study is to investigate the effect of pulp consistency on refining response of the fibre materials. Results show that refining at consistency of 6-10% with the MC refiners effectively preserves fibre length, and the pulp after refining contains higher proportion of long fibre fractions in comparison with the pulp refined at consistency of 3-4% with LC refiners. It is also found in the experiments that physical properties of the paper made from the pulp refined at consistency of 6-10% with the MC refiners obviously enhance, and specific energy consumption during refining reduces by 30% compared with the refining at consistency of 3-4% with LC refiners.

Use of green chemical technologies in an integrated biorefinery

A new concept is demonstrated for an integrated close to zero waste wheat straw biorefinery combining two novel green technologies, CO2 extraction and low temperature microwave pyrolysis, to produce a variety of products, including energy and CO2 which can be internally recycled to sustain the processes. CO2 adds value to the process by extracting secondary metabolites including fatty acids, wax esters and fatty alcohols. Low temperature microwave pyrolysis (<200 °C) is shown to use less energy and produce higher quality oils and chars than conventional pyrolysis. The oils can be fractionated to produce either transport fuels or platform chemicals such as levoglucosan and levoglucosenone. The chars are appropriate for co-firing. The quality of the chars was improved by washing to remove the majority of the potassium and chlorine present, lowering their fouling potential. The economic feasibility of a wheat straw biorefinery is enhanced by intergrating these technologies.

Copper Release Behavior in Two Calcareous Soils Amended with Three Organic Materials

Understanding time-dependent copper (Cu) desorption behavior is critical for improving the prediction of Cu availability in soils. This study was conducted to evaluate the influence of municipal waste compost, sheep manure, and wheat straw on desorption characteristics of Cu and to evaluate the suitability of different kinetic models to describe the Cu release pattern in two calcareous soils. Diethylenetriaminepentaacetic acid (DTPA) and ethylenediaminetetraacetic acid (EDTA) were employed to extract Cu from soils. Best-fitted kinetic models including Elovich, simple Elovich, two-constant rate, and parabolic diffusion were selected based on their low standard error and high coefficient of determination. Extractable copper significantly decreased with increasing rates of sheep manure and wheat straw but increased with increasing rates of municipal waste compost amendment. Results revealed that copper was more readily desorbed from clay soil compared to silt loam soil. The copper desorption patterns were almost similar for both extractants; however, EDTA extracted more Cu from soils.

Thermostable xylanase production and partial purification by solid-state fermentation using agricultural waste wheat straw

A locally isolated strain of Trichoderma harzianum was studied for production of xylanase (EC 3.2.1.8) using lignocellulosic substrates for solid-state fermentation. Among the different substrates used, wheat straw produced the highest yields (146 IU/ml). The influence of temperature, pH, moistening agents, moisture level, carbon sources, nitrogen sources, pretreatments and metal ions were evaluated with respect to xylanase production. Highest xylanase production was obtained using wheat straw after 12 days of incubation. Different substrate combination ratios and the effect of particle size were also checked against xylanase production. Maximum xylanase production was observed in a wheat straw/rice straw ratio of 1:1, with a particle size of 0.45–0.5 mm. Media supplementation with xylose as a carbon source in a ratio 1:5 (carbon source/substrate) gave maximum activity (157 IU/ml). Nitrogen supplementations from yeast extract produced xylanase activity of 141 IU/ml. Optimum xylanase production was observed at 30°C and pH 5.0. Xylanase production was enhanced in the presence of Ca2+ and Zn2+ ions. Ammonium sulfate fractionation (20–80% saturation) of partially purified xylanase yielded 76.5% of the enzyme with a 3.53-fold purification. The molecular weight of xylanase was found to be ca. 29,000 Da by SDS–PAGE.

Agro-industrial waste ‘wheat bran’ for the biosorptive remediation of selenium through continuous up-flow fixed-bed column

Present study deals with the utilization of an agro-industrial waste wheat bran for the remediation of selenium species, Se(IV) and Se(VI) by continuous up-flow fixed-bed column system. Laboratory-scale column tests were performed to determine potentiality of wheat bran at various bed height, flow rates and initial metal ion concentration and it was found to be very potential biosorbent as it showed good sorption capacities of 72.54 μg/g and 62.51 μg/g for Se(IV) and Se(VI) respectively. Different models like Bed Depth Service Time (BDST), Thomas and Yoon–Nelson were applied to the experimental sorption data. The data showed very good fit to BDST model and sorption capacities ( N o) computed using BDST model were 26,664 μg/L and 26,400 μg/L for Se(IV) and Se(VI) respectively. Also Yoon–Nelson model was found to show good agreement with the experimental kinetic results as compared to the Thomas model. Wheat bran was amenable to efficient regeneration with 10% NaOH. The biosorbent retained most of its original uptake capacity over three cycles of use. The excellent reusability of the biosorbent could lead to development of a viable metal remediation technology. Life factor calculation revealed that biosorbent bed will have sufficient capacity to avoid breakthrough at time t = 0 up to 12.17 cycles for Se(IV) and 6.28 cycles for Se(VI) and bed would be completely exhausted after 56.89 cycles for Se(IV) and 18.73 cycles for Se(VI).

The Perception of Farm Advisors about the Role of Wheat Self Sufficiency Plan (WSP) in Reducing Wheat Waste in Iran

The Perception of Farm Advisors about the Role of Wheat Self Sufficiency Plan (WSP) in Reducing Wheat Waste in Iran

Hydrogen production by combined dark and light fermentation of ground wheat solution

Abstract Ground waste wheat was subjected to combined dark and light batch fermentation for hydrogen production. The dark to light biomass ratio (D/L) was changed between 1/2 and 1/10 in order to determine the optimum D/L ratio yielding the highest hydrogen formation rate and the yield. Hydrogen production by only dark and light fermentation bacteria was also realized along with the combined fermentations. The highest cumulative hydrogen formation (CHF = 76 ml), hydrogen yield (176 ml H 2 g −1 starch) and formation rate (12.2 ml H 2 g −1 biomass h −1 ) were obtained with the D/L ratio of 1/7 while the lowest CHF was obtained with the D/L ratio of 1/2. Dark–light combined fermentation with D/L ratio of 1/7 was faster as compared to the dark and light fermentations alone yielding high hydrogen productivity and reduced fermentation time. Dark and light fermentations alone also yielded considerable cumulative hydrogen, but slower than the combined fermentation.