Stalk Residues Research Articles

Enrichment of functional drinks using grape pomace extracts, analysis of physicochemical indicators

A large amount of residues called secondary raw materials are formed during grape processing, the majority of which are pomace-containing seeds. Pomace is obtained by crushing grapes with subsequent juice separation and appears as a mass consisting of skin, seeds, as well as stalk and comb residues. When compared to the control, the amount of skin in the fermented pomace increased 15 %, while the amount of seeds decreased by about 50 %. The objects of research is juice, wine materials, functional drinks, technological methods and means. The problem is that the samples of juice and dark wine prepared by the "White method" are not provided with a sufficient amount of extract substances, especially compounds that provide functionality. The results of the experiment show that adding 25–30 % wine-alcohol extract of marc to the wine material obtained by the “white method” from the Bayanshira grape variety, and adding 25–30 % alcohol-juice extract to the juice obtained from its own stream, give a positive result. Compared to the control, in the prepared functional wine samples the content of phenolic compounds increased by 100 mg/dm3, and there was also an increase in the amount of vitamins B2, C, PP, B6 and resveratrol. Rational technological parameters for the extraction of biologically active substances from grapes and their structural components have been established. It has been established that mixing fermented pomace with a 30 % wine-alcohol (juice-alcohol or aqueous-alcohol solution) extractant in a 1:3 hydromodule gives the best result. It is of practical importance to enrich low-extracted juices and wines with extracts obtained from the solid parts of the cluster to produce functional drinks

Sustainable Zn2+ removal using highly efficient, novel, and cost-effective chitosan-magnetic biochar composite.

This study focused on the development of a sustainable and low-cost adsorbent derived from the chitosan-biochar composite for the removal of Zn2+ from an aqueous solution. Biochar was prepared from cotton stalk residue by pyrolysis at 600°C for 2h, modified with FeCl3, and composed with chitosan in various ratios (1:3, 1:1, 3:1), leading to the formation of an efficient, thermally stable, and rich with functional groups chitosan-biochar composite denoted as CHB-Fe-CS. Functional groups (hydroxyl, carboxyl, and amine) were identified as key contributors to the adsorption mechanism. Langmuir isotherm (R2 = 0.99) and Pseudo-Second order (R2 = 0.99) were best fitted models with the experimental results indicating chemisorption-driven monolayer adsorption. The results revealed CHB-Fe-CS (3:1) composite obtained the highest adsorption capacity of 117.50mg/g for Zn2+ under optimal conditions viz., 180min batch time, 500mg/l metal concentration, 4g/l adsorbent dosage, 40°C solution temperature, and 5.0 pH. Regeneration of the used adsorbent was performed using 0.2mol/l HCl and obtained desorption efficiency of 67.48% and 51.48% after the 4th and 8th cycles. The adsorption mechanisms were dominated by ion exchange, surface complexation, and electrostatic attraction compared to intra-particle diffusion and physisorption. The CHB-Fe-CS demonstrated an economical, environment friendly, and good performing adsorbent for water decontamination.

A Study of the Relationship between Initial Grape Yield and Soil Properties Based on Organic Fertilization

Increasing the use of organic fertilizers is an effective measure to improve, increase soil fertility and maintain crop yields. The aim of this study was to investigate the influence of different types of organic fertilizers on the early yield of grapes and soil parameters, as well as the relationship between soil parameters and grape yield under fertilization conditions. The ‘Shine Muscat’ grape was used as the material, with early maturing cultivation in the solar greenhouse. From the time of grape planting, three-year continuous fertilization management was carried out using five types of base fertilizers: chemical fertilizer (CK), fermented corn stalk residue (A1), mature sheep manure (A2) and two types of commercial organic fertilizers (B1 and B2). In the third year, berry and soil samples were collected to determine grape yield and evaluate soil physicochemical properties, nutrient status and changes in enzyme activity, studying the relationship between grape yield and soil indicators. The results show that compared to CK, the grape yields with B1 and B2 increased by 19.04% and 16.26%, respectively, while A1 and A2 decreased by 24.09% and 18.97%. Organic fertilizer application reduced soil bulk density, increased soil porosity, enhanced soil organic matter content and effectively buffered soil pH levels. Two types of commercial fertilizers (B1 and B2) improved soil total nitrogen, total phosphorus, total potassium, available nitrogen and available phosphorus content to varying degrees. All organic fertilizer treatments effectively increased soil enzyme activity, except for soil sucrase activity. Through correlation and regression analyses, it was found that in this study, the levels of available nitrogen, available potassium and soil saccharase activity were most closely related to early grape yield. Their influence on grape yield was in the order of available nitrogen > soil saccharase activity > available potassium. Therefore, with a combined organic and inorganic basal fertilization system, the fertilizer nutrients are more comprehensive and help to increase the productivity of grapes at the beginning of the fruiting period. Nitrogen and phosphorus are very important in the maintaining of grape yields and improving sucrose activity in the soil through the application of organic fertilizers cannot be ignored when increasing yields.

Optimization and characterization of paddy stalks-based activated carbon by physical activation: Box-Behnken design approach

Improper disposal of paddy stalks residue via open burning or soil incorporation creates contamination hazards by releasing particulate matter, residue ash, and breakdown chemicals into the environment. This study aimed to repurpose these stalks by converting them into activated carbon. Box Behnken Design BBD within the response surface methodology (RSM) framework was adopted. The independent variables of the preparation conditions were the holding time, heating rate and activation temperature. The optimization process response was the surface area of activated carbon. The paddy stalks based activated carbon (PSAC) was subjected to a suite of physicochemical characterization techniques including BET, FTIR, XRD and SEM. The highest surface area of 488.6 m2/g was obtained at heating rate of 10 min/°C, contact time of 120 min and activation temperature of 500 °C. The statistical analysis showed that contact time achieved the highest significancy, followed by activation temperature and heating rate. The activated carbon exhibited pore sizes spanning from 2 nm to over 269 nm, creating pores sufficiently broad to fit some toxic contaminants. The findings demonstrate the viability of paddy stalks for activated carbon production, introducing a sustainable stalk residue disposal solution that promotes environmental sustainability.

The Effects of Sunflower and Maize Crop Residue Extracts as a New Ingredient on the Quality Properties of Pork Liver Pâtés.

The present study aimed to evaluate the antioxidant capacity of ethanolic extracts from post-harvest sunflower and maize stalk residues, and their impact on the chemical composition, physicochemical parameters, lipid oxidative stability, microbiological properties, and sensory characteristics of pork liver pâtés over a 90-day storage period. Four formulations were prepared: a control group (CON), a batch with butylated hydroxytoluene as a synthetic antioxidant (BHT), 1% ethanolic extract from sunflower residues (SSRE), and 1% ethanolic extract from maize residues (MSRE). The MSRE had a higher total phenol content and showed better antioxidant activity relative to the SSRE (p < 0.01). The addition of SSRE decreased the lightness and increased the redness in the pork liver pâtés, with these pâtés showing the highest total color difference compared to the control (p < 0.01). The crop extracts increased the n-6 and total PUFA contents in pâtés and improved the PUFA/SFA ratio (p < 0.01). Formulations containing crop residue extracts showed higher TBARs and POV values than the control and BHT group (p < 0.01), indicating a pro-oxidant effect and accelerated lipid oxidation in pâtés during storage. As far as microbiological quality, the presence of crop residue extracts decreased the total viable count, lactic acid bacteria, and psychotropic aerobic bacteria (p < 0.01). The incorporation of crop extracts in the pork pâtés impaired their sensory quality, particularly color, odor, aroma, and flavor, and decreased their overall acceptability. These results indicated that, while the crop residue extracts were not as effective as synthetic antioxidants in preserving the lipid stability of pâtés, they demonstrated potential for enhancing the microbial quality of this type of meat product.

Harvest load transfer sites influence sugarcane billbug (Coleoptera: Curculionidae) spatiotemporal injury in sugarcane.

The sugarcane billbug, Sphenophorus levis Vaurie 1978, is a key soil-dwelling insect pest of sugarcane in Brazil and greatly affects plant development and yield. This insect presents an aggregated distribution pattern in production fields. The reasons for such behavior include intraspecific communication and attractivity due to the fermentation of sugar in stalk residues. During mechanized harvesting, part of the harvested material usually falls in the load transfer sites, becoming a potential source for increasing the infestation. We therefore evaluated whether producing areas near the harvest load transfer sites are more prone to S. levis injury. There are greater chances of finding billbug injury within a radius of 740 m from the harvest load transfer site. Additionally, injured areas are estimated to expand 11.96% each growing season. Our spatiotemporal models support higher injured areas surrounding the harvest load transfer site and show clear and significant signs of increased injury levels compared to the initial growing season surveyed. Our results reinforce the importance of harvest transfer sites in the dispersion and propagation of the sugarcane billbug. Based on this knowledge, sugarcane millers and growers can adopt preventive and remedial practices within the loading sites that can potentially contribute to the successful management of this insect pest. © 2023 Society of Chemical Industry.

Upgrading of Corn Stalk Residue and Tannery Waste into Sustainable Solid Biofuel via Conventional Hydrothermal Carbonization and Co-Hydrothermal Carbonization

Upgrading of Corn Stalk Residue and Tannery Waste into Sustainable Solid Biofuel via Conventional Hydrothermal Carbonization and Co-Hydrothermal Carbonization

Development of sustainable biomass residues for biofuels applications

A comprehensive understanding of physiochemical properties, thermal degradation behavior and chemical composition is significant for biomass residues before their thermochemical conversion for energy production. In this investigation, teff straw (TS), coffee husk (CH), corn cob (CC), and sweet sorghum stalk (SSS) residues were characterized to assess their potential applications as value-added bioenergy and chemical products. The thermal degradation behavior of CC, CH, TS and SSS samples is calculated using four different heating rates. The activation energy values ranged from 81.919 to 262.238 and 85.737–212.349 kJ mol−1 and were generated by the KAS and FWO models and aided in understanding the biomass conversion process into bio-products. The cellulose, hemicellulose, and lignin contents of CC, CH, TS, and SSS were found to be in the ranges of 31.56–41.15%, 23.9–32.02%, and 19.85–25.07%, respectively. The calorific values of the residues ranged from 17.3 to 19.7 MJ/kg, comparable to crude biomass. Scanning electron micrographs revealed agglomerated, irregular, and rough textures, with parallel lines providing nutrient and water transport pathways in all biomass samples. Energy Dispersive X-ray spectra and X-ray diffraction analysis indicated the presence of high carbonaceous material and crystalline nature. FTIR analysis identified prominent band peaks at specific wave numbers. Based on these findings, it can be concluded that these residues hold potential as energy sources for various applications, such as the textile, plastics, paints, automobile, and food additive industries.

Synergistic Effects and Kinetics in Co-Pyrolysis of Waste Tire With Five Agricultural Residues Using Thermogravimetric Analysis

Abstract Continued social and mobility development has caused a sharp increase in the number of waste tires, increased environmental pollution, and waste of limited resources. Agricultural residues as a bioresource, which has drawn increased attention in recent years. The thermochemical conversion of waste tires and agricultural residues and their mixtures offers important prospects for scientific development, which can provide energy security and a much reduced environmental footprint. In this paper, pyrolysis of waste tires and its co-pyrolysis with maize stalk, wheat straw, cotton stalk, rape straw, or peanut shell agricultural residues, in mass ratios of 1:1 were investigated at different heating rate using thermogravimetric analysis. The kinetic parameters were calculated using Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) kinetic models at heating rates of 20, 30, and 50 °C/min. The synergistic effect between waste tires and agricultural residues was explored by calculating the deviation between the experimental and calculated values. The results showed the presence of a synergistic effect between the co-pyrolysis of waste tires and the residual agricultural residues. In the kinetic analysis, activation energies of waste tires, agricultural residues, and their mixtures were calculated using the two models. The reaction followed a multistage reaction mechanism. The differential thermogravimetry behavior of the mixture was similar to the weighted aggregate results of the waste tire and agricultural waste samples, pyrolyzed separately. These results provide some insights into the combined treatment of waste tires and agricultural waste residues.

Long‐term fertilization and plastic film mulching modify temporal incorporation of 13C/15N‐labelled particulate organic matter

AbstractPlastic film mulching (PFM) is critical for agricultural planting and maximizing production in semiarid and arid areas. Particulate organic matter (POM) is assumed to be a sensitive indicator for evaluating the effects of different agricultural practices on soil fertility and the soil organic carbon (SOC) pool. Soil aggregates have the function of ‘wrap’ and protect the POM stored in them. However, there is limited information regarding how PFM and fertilization jointly influence the dynamic changes of newly added stalk‐derived POM in brown earth. Consequently, an in‐depth study of the fate of carbon (C) and nitrogen (N) derived from maize stalk residues within the particulate organic carbon (POC) and particulate organic nitrogen (PON) fractions in soil aggregates was undertaken. Its outcome would contribute to better predictions on the active organic matter components sequestered in the soil. The dynamics and accumulation of newly added maize stalk C and N as POC and PON in different soil aggregates (using the dry sieving method divided into &gt;2, 1–2, 0.25–1 and &lt;0.25 mm) were analysed by an in situ 13C/15N‐tracing technique under PFM and different fertilization treatments. Over 360 days of cultivation, the POC and PON contents were significantly (p &lt; 0.05) larger in the nitrogen (N) and organic manure (M) treatments than in the MN (manure combined with nitrogen) and Control treatments. The PFM treatment accelerated the decomposition of maize stalk C in the N fertilizer treatment, with an increase of 64% in stalk‐derived POC after the 1‐day cultivation period. Stalk‐derived POM tended to accumulate in &lt;0.25 mm microaggregates in the early cultivation period and then decreased rapidly with the extension of the cultivation period affected by PFM coupled with fertilization. However, stalk‐derived POM accumulation in macroaggregates (&gt;0.25 mm) fluctuated over the 360‐day cultivation period. Accordingly, PFM application and fertilization practices had important effects on the accumulation of newly added stalk‐derived POM in soil aggregates. We conclude that the accumulation of maize residue POM was primarily affected by soil fertilization type, rather than by the presence or absence of PFM. These results provide new insights into agricultural management strategies for improving soil carbon sequestration capacity.

Anaerobic digestion of lignocellulosic waste for enhanced methane production and biogas-digestate utilization

Lignocellulosic biomass is an important source for nutrient management in agricultural systems and has a largely unexploited potential for biogas production. The digestates from the anaerobic digestion (AD) process are widely used in agriculture systems due to their nutrient composition and organic matter, making them a valuable source for plants. As a result, methane (CH4) production from AD of lignocellulosic biomass waste, such as rice straw, corn stalk, and grape stalk, was determined in this study, and their anaerobic digester residues were studied at various concentrations to investigate their potential on tomato plant growth and fruit yield. The biogas and CH4 yields of the pretreated rice straw, corn stalk, and grape stalk were determined through the AD process for 72 days, and the results revealed a gradual increase in the cumulative biogas and CH4 production until the end of the AD process (72 days). The cumulative biogas from rice straw, corn stalk, and grape stalk was 359.3, 309.9, and 215.1 L/kg VS, respectively. However, the biogas production of rice straw was higher than that of corn stalk, and grape stalk by 15.6% and 67%, respectively. The cumulative CH4 yield of rice straw was higher than that of corn stalk, and grape stalk by 21.1% and 76.3%, respectively. The results also showed that tomato growth significantly increased under grape stem residue (GSR) more than under rice straw residue (RSR) and corn stalk residue (CSR), as well as under untreated control and control infected with Fusarium oxysporum f. sp. lycopersici (FOL). The increase in bioreactor residue concentration resulted in a significant increase in tomato growth parameters, crop yield, and tomato quality. The results confirmed that 20% of GSR increased the tomato's physical and chemical properties compared with control, RSR, and CSR. The soil content of total nitrogen, phosphorus, and potassium gradually increased with the increase in residue concentrations before and after AD, and the maximum concentration was obtained at 25% of GSR. Therefore, anaerobic digestate could be economically viable, which can be a good solution for sustainable lignocellulosic biomass waste management and plant growth.

Establishment of correlation between reaction kinetics and carbon structures in the char gasification process

For a gasification process, the char-CO2 gasification is the controlling step worthwhile to be deeply investigated. The article chosen corn stalk (CS), poplar sawdust (PS) and bagasse residue (BR) as the typical waste species derived from agricultural, forestal and industrial sources. The char-CO2 gasification behavior, reaction kinetics and carbon structure were studied to reveal the intrinsic factors determining the reaction kinetics. Generally, the carbon conversion and maximum conversion rate were influenced by the feedstocks species and char preparation temperatures, as influenced by ash proportion, potassium content in ash and carbon structure of char. The char-CO2 reaction for CS was subject more to the catalytic effect of alkali compositions, while pore structure affected more the gasification reaction for PS char. The isoconversional kinetic analysis indicated that the gasification reaction became stable at carbon conversion of 0.5. Subsequently, sectionalized kinetic parameters were calculated for the initial gasification temperature to the temperature reaching 50% conversion. The result showed that high initial gasification temperature increased the char-CO2 gasification barrier to hardly start the reaction but accelerate the reaction rate. The carbon structure analyses further clarified that the reaction activation energy was highly related to the microcrystalline structure of carbon, while the reaction rate was more determined by carbon pore structure.

Preparation of microcrystalline cellulose from agricultural residues and their application as polylactic acid/microcrystalline cellulose composite films for the preservation of Lanzhou lily

Microcrystalline celluloses were isolated from four agricultural residues, including sweet sorghum stalk, Jerusalem artichoke stalk, grains stillage, and Chinese herb residue, and characterized in terms of physicochemical and structural properties. The obtained microcrystalline celluloses were composited with polylactic acid as a packing film for the preservation of Lanzhou lily. All the agricultural residues-derived microcrystalline celluloses were in cellulose Iβ structure with high purity and good thermal stability. Microcrystalline celluloses from sweet sorghum stalk had a higher degree of polymerization (327) and crystallinity (70.52 %) than others. The preservation effect of lily bulbs packaged by films were significantly improved indicated by the lessened weight loss rate and the meliorative hardness and whiteness, which ascribe to the repressed oxidation reactions. Polylactic acid/microcrystalline cellulose composite films prepared from sweet sorghum straw have been proved the most effective. This work could offer a value-added outlet for agricultural residues to produce microcrystalline celluloses-based biocompatible films for preservation of Lanzhou lily.

Investigation of the heat release rate and particle generation during fixed bed gasification of sweet sorghum stalk

Sweet sorghum (SS) is an agricultural crop that is produced commercially in Nigeria. The crop has a high biowaste energy in its stalk, which is an attractive source of bioenergy in rural areas where it is produced. The residue–to-produce ratio (RPR) of the crop is 1.25 kg of biowaste for 1 kg of SS produced. The solid residue that results from the crop can be subjected to gasification to produce combustible gases: carbon monoxide (CO), hydrocarbon gases (total hydrocarbons) and hydrogen. The combustible gases can be piped into a burner for heat or into a Compression Ignition (CI) engine for electricity generation. This will enhance energy security as well as energy equity in rural areas in Nigeria and sub-saharan African countries where the crop is also produced. This research was aimed at optimising the gasification of SS stalk residue to maximise the yield of combustible gases from the first stage of the process. The restricted ventilation cone calorimeter method was used to gasify SS stalks on a laboratory scale. The test was carried out at air flow rates per exposed flat surface area of 9, 11.2, 12.9, 14.3, 15.5, 16.3, and 19.2 g/s·m2 respectively, which controls the gasification rate or power output. The speciation of the gases that evolved from the gasification of the biomass samples was carried out by an FTIR that was calibrated for 60 species. Current uses of biomass residues in open fire heating generates toxic fine particulate emissions and this work aimed to show that this was not a greater problem with gasification. A dynamic electrical mobility particle spectrometer (DMS500) was used to measure the particulate size distribution and concentration, as an efficient gasifier should not be generating major yields of soot, which would be a problem for a downstream reciprocating engine. The optimum equivalence ratio (Ф) for the best energy transfer to the gaseous products was 2.1, which was similar to previous work on pine using this equipment where the optimum equivalence ratio was 2.8. The hot gases efficiency at the optimum Ф was 81%, which compares well to that of 78% for pine.

Biomass, lignocellulolytic enzyme production and lignocellulose degradation patterns by Auricularia auricula during solid state fermentation of corn stalk residues under different pretreatments

Current work proposes an innovative substitute cultivation strategy for Auricularia auricula that connects efficient lignocellulose biodegradation of corn stalk by pretreatment with mycelium growth of Auricularia auricula under solid state fermentation. The growth promotion effect of mycelium was as follows: alkali pretreatment > alkali combined with ozone pretreatment > ozone pretreatment > high-temperature water pretreatment (control). The highest cellulose degradation (35.38%) was observed in alkali pretreatment group (P < 0.05), while the maximum lignin loss of 28.10% was reached in the ozone pretreatment group. Correlation analysis showed that both cellulose and lignin could be used as carbon sources to promote mycelium growth, but the effect of cellulose was better. High activities of β-glucosidase (2.92 IU/g) and filter paper enzyme (2.92 IU/g) were observed in alkali pretreatment group on Day 6 and 8, respectively, which were significantly correlated with the change of cellulose degradation rate (P < 0.01).

Characterization of Bio-oil, Bio-char, and Pyro-gas derived from cotton stalk slow pyrolysis - as sustainable energy sources

The untapped energy present in this cotton stalk residue is one of the major environmental threats due to its field burning. In this research paper, slow pyrolysis process has been performed on cotton stalk having particle size 0.85 mm at 300°C, 400°C, and 500°C, at 10°C/min heating rate and 1-hour residence time. The process produced bio-oil, bio-char and pyro-gas. Physiochemical properties, GC-MS analysis, stability analysis and miscibility analysis of bio-oil have been carried out to ensure its feasibility as energy source. To ensure suitability of bio-char as soil nutrient and energy sources, its elemental analysis, metal element analysis and microscopic examination have been performed. Pyro-gas is characterized to find its suitability as energy source for heating purpose during pyrolysis process by recirculating. The maximum yield for bio-oil and Pyro-gas is 36.60 wt.% and 25.25 wt.%, respectively at 500°C, while maximum yield for char is 58.54 wt. % at 300°C. Result of physiochemical properties of bio-oil reveals remarkable variation as compare to diesel whereas GC-MS analysis found bio-oil as complex mixture. 0.02349 cst/hr. aging rate of bio-oil shows good stability at room temperature. Physiochemical properties of bio-oil vary with pure diesel causes phase separation of bio-oil and diesel during blending. Bio-oil - diesel Stabilized emulsion has been achieved by addition of 6 wt. % of n-butanol as co-solvent. Characterization and microscopic examination of bio-char favours usage of char as soil nutrient and energy substitute. The Pyro-gas analysis confirms its suitability as energy substitute during entire process, as it contains a substantial amount of carbon dioxide and methane.

Development of Cotton stalk harvesting machine for ex-situ application

Cotton (Gossypium hirsutum) is an important commercial crop in India. Annually 30.79 million tons of cotton stalk residue is being generated in India. In India, after harvesting cotton lint, cotton stalks are removed by either manual uprooting or cutting them using sickle above the ground level, which is a laborious operation and contributes to increase in crop production. After removing cotton stalks from field, farmers are burning cotton stalks in their fields. Burning of stalks increases CO2, CO, N2O and NOx in the atmosphere which leads to increase in air pollution. Instead of burning the stalks in fields, cotton stalks have the potential to be used for ex-situ application such as, raw material for briquettes due to its high lignocellulosic nature. Ex-situ utilization cotton stalk aids in generating additional income to farmers. In order to utilize the cotton stalk for ex-situ application a cotton stalk harvester was developed and evaluated in the field conditions which gave the following results; mean chopped length 122.7 mm, bulk density 197.86 kgm-3, fineness modulus 1.828, machine output of 1259.85 kgh-1, chopping height 118.6 mm field capacity 0.17 ha h-1, and fuel consumption of 7.54lh-1.

PRODUCTION OF CELLULOLYTIC ENZYMES FROM TRICHODERMA SP. STRAINS FOR FERMENTATION OF GRAPE RESIDUES AS SOLID SUBSTRATE REUSING WINE RESIDUES

Currently, the agri-food society increases waste to the environment with potential environmental impacts and one of them is the wine industry, generating organic waste in short periods, showing that the use of fertilizers in the vineyard, packaging materials, and their waste management suchas grape production in wineries and wine production are responsible for environmental impacts that are highly polluting. In this aspect, grape extracts and grape pomace are rich sources of polyphenols, so in the present study, we evaluated the obtaining of cellulolytic enzymes, through fermentation in solid-state (FES) with strains of Trichoderma sp. Grape pomace and grape stalk residues were used, also Carboxymethylcellulose (CMC) at 0.5 % and mineral solution were added to the (FES). The results showed that grape stalk is a better substrate than grape pomace. In addition, the enzyme activity with (CMC) 0.5 % was 0.1289 U/mL and with saline solution was 0.1286 U/mL. Therefore, it is concluded that cellulolytic enzymes can be obtained by (FES) from grape stalk supplemented with CMC 0.5 %. These results provide relevant data on the regression coefficients to the experimental data resulting in the high potentiality of cellulase production about fungal growth and its enzymatic secretion.

Effects of Corn Stalks and Urea on N2O Production from Corn Field Soil

Returning corn stalks to the field is an important and widely used soil management practice which is conducive to the sustainable development of agriculture. In this study, the effects of corn stalks and urea on N2O production in corn field soil were investigated through a 21-day incubation experiment. This study showed that increasing amounts of urea added to soil with a history of corn cultivation leads to increasing overall N2O emissions, by increasing both the intensity and the duration of emissions. Although N2O production was affected primarily by urea-derived NH4+-N and NO3−-N, its main source was native soil nitrogen, which accounted for 78.5 to 94.5% of N2O. Returning corn stalk residue to the field reduced the production of N2O, and the more urea was applied, the stronger the effect of corn residue on reducing N2O emissions. Combining the application of corn stalks and urea could reduce the concentration of NH4+-N and NO3−-N derived from urea, and then reduce the substrate required for N2O production in nitrification and denitrification processes. In addition, the combined application of corn stalks and urea could effectively inhibit the abundance of key N2O-producing genes AOA amoA, nirS and nirK.

Enhanced lactic acid production from P2O5-pretreated biomass by domesticated Pediococcuspentosaceus without detoxification.

Expensive cellulase and complex detoxification procedures increase the cost of biomass lactic acid fermentation. Therefore, it is of great significance to develop a robust method to ferment lactic acid using biomass by avoiding cellulase and detoxification. This study demonstrates the advantage of combining mechanocatalytic P2O5 pre-treatment and strain domestication. We show that an enzyme-free mechanocatalytic saccharification process by combining mix-milling of P2O5 with biomass and successive hydrolysis produces a fermentable hydrolysate with much less inhibitory compounds than the hydrolysates obtained by conventional methods; only 5-HMF, furfural and acetic acid were detected in the biomass hydrolysate, and no phenolic inhibitors were detected. Pretreatment of biomass with P2O5 not only avoided cellulase, but also obtained less toxic hydrolysate. Furthermore, the Pediococcuspentosaceus strain gained superior inhibitor tolerance through domestication. It could tolerate 17.1g/L acetic acid, 12.5g/L 5-HMF, 11.9g/L guaiacol and 11.5g/L furfural and showed activity in decomposing furfural and 5-HMF for self-detoxification, allowing efficient lactic acid fermentation from biomass hydrolysate without detoxification. The lactic acid concentration and conversion rate fermented by domesticated bacteria were increased by 113.5% and 22.4%, respectively. In addition, the domesticated bacteria could utilize glucose and xylose simultaneously to produce lactic acid selectively. The combination of P2O5 pre-treatment and strain domestication to ferment lactic acid is applied to several biomass feedstocks, including corn stalk, corn stalk residue and rice husk residue. Lactic acid concentrations of 29.8g/L, 31.1g/L, and 46.2g/L were produced from the hydrolysates of corn stalk, corn stalk residue and rice husk residue, respectively.