Maize Cob Research Articles

Innovative biochar and organic manure co-composting technology for yield maximization in maize-black gram cropping system

The collective utilization of biochar and organic manure represents the profit to plants and nutrient cycling. In this experiment, the maize (stalk and cob) biomass was pyrolyzed at 600 °C and morpho-mineralogically characterized. The scanning electron microscope (SEM) image represented cross-linked pores and feathery plate–like layer construction on the surface of biochar. The 75:25 ratio combinations of organic manure and biochar were the best for developing low-cost biochar co-compost technology. The maximum increase in pH was observed in biochar-poultry manure (7.05) co-compost followed by pig manure (6.97), goat manure (9.93), vermicompost (6.85), and FYM (6.83) co-compost. The release of cumulative CO2 decreased with increase in biochar ratio in biochar co-compost mixture. The organic manure/biochar (co-compost) ratio at 75:25 enhanced maximum yield in poultry manure (4528 and 1027 kg/ha) followed by goat manure (4378 and 1016 kg/ha), vermicompost (4278 and 986 kg/ha), pig manure (4218 and 956 kg/ha), and FYM (4178 and 949 kg/ha) for maize and black gram, respectively. The poultry75+BC25 results in maximum grain nitrogen content in both maize and black gram and minimum with FYM25+BC75. Lastly, with increase in biochar ratio in co-compost, the specific leaf weight and chlorophyll content significantly increased. Thus, the encouraging role of biochar co-compost on crop growth, yield, soil health, and physiology proposes that it is a superior technique to overcome biochar’s intrinsic nutrient deficit, making it a proper way serving to refine farm-scale nutrient cycles.

Application of cold-adaptive Pseudomonas sp. SDR4 and Mortierella alpina JDR7 co-immobilized on maize cob in remediating PAH-contaminated freeze-thawed soil

There are large areas of contaminated soils with low- and medium-concentration of polycyclic aromatic hydrocarbons (PAHs) in the coldest regions of the earth, potentially threatening ecological safety and human health. Using maize cobs (MC) as the carrier, two cold-adaptive PAHs-degrading microorganisms, bacterial (Pseudomonas sp., SDR4) and fungal (Mortierella alpine, JDR7) strains were co-immobilized. The degradation characteristics of phenanthrene (Phe), pyrene (Pyr) and benzo[a]pyrene (BaP) in freeze-thawed soil by both co-immobilized and free microorganism were studied. The removal rate of Phe, Pyr and BaP using the co-immobilized fungal-bacterial consortium within 60 d was 59.2±3.7%, 46.6±3.3%, and 36.8±2.7%, respectively, which was obviously higher than that of free fungal-bacterial consortium in the same time. Ten percent (w/w) was the optimal amount of inoculum for PAH degradation in the co-immobilized fungal-bacterial consortium. Under low-temperature conditions, when the initial concentration of PAH was between 10-100 mg•kg−1, the immobilized cold-adaptive fungal-bacterial consortium displayed the desired degradation of PAHs. The scanning electronic microscope (SEM) observation and mass transmission showed that the microstructure of co-immobilized mixed system was beneficial to the growth of SDR4 and JDR7 at low temperature. These results imply that the cold-adaptive fungal-bacterial consortium, co-immobilized on MC, has the potential for application in remediating PAH contaminated soil under the freeze-thawing environment.

Comparative Anaerobic Co-Digestion Effects of Some Agricultural Biomass on Their Digestates Biochemical Properties

The huge agro-industrial biomass wastes had engendered the need for appropriate treatment technology, which could be deployed to sustainably manage and convert them to useful by-products. Consequently, the comparative anaerobic co-digestion effects of some agricultural biomass on their digestates biochemical properties were conducted. Twelve (12) replicates slurries from four mixing ratios of maize cob, poultry droppings and cow dung (1:0, 1:0, 1:0 and 1:1:1) as treatments TA, TB, TC and TD respectively, were separately digested in 13.6L locally fabricated batch-digester reactors, for eight weeks. Proximate and amino acids constituents were evaluated by standard procedure prior to and at post anaerobic digestion (AD). The biogas yields followed the sequence of TD (2200.7ml/kg) > TB (2197.9ml/kg) >TC (2079.0ml/kg) > TA (1713.2ml/kg), showing co-substrate effects. Proximate assay depicted a decrease in crude lipid across the treatments, with TC (86.82%) and TD (64.66%) as highest and lowest values. Crude fiber and nitrogen free extract had similar observation, apart from TB and TC with increased values. Percentage moisture and percentage ash contents increased across treatments. Carbon - Nitrogen ratio reduction (C/N Reduction) was in the range of 12.94 -85.79%. The Percentage chemical oxygen demand reduction (CODR), followed the order of TA (46.81%) > TB (34.15) >TC (25.81%) >TD (8.00%). There was increased histidine, glycine, cystine, methionine, total nonessential amino acids (TNEAA) and total aromatic amino acids (TArAA), with decrease in aspartic acids and serine. Percentage arginine, threonine, glutamic acid, proline, alanine, isoleucine, tyrosine, total amino acids (TAA) and total essential amino acid (TEAA) decreased only in TB. While, only TA had Percentage increased lysine (25.00%), valine (40.98%) and TArAA (6.13%), with phenylalanine unaffected (0.00%), Percentage leucine of TB (60.14%) and TD (23.08%) were reduced after AD. The process had revealed the alternative waste management, energy options, and useful industrial by-products for agro-allied industries.

Life cycle analysis of a biorefinery for activated carbon and biomethane production

A Life Cycle Analysis (LCA) based on ReCiPe 2016 model of a biorefinery case-study was performed. On the basis of an existing Portuguese Anaerobic Digestion plant, the proposed biorefinery hypothesized the use of (i) Maize Cob Waste (MCW) as co-substrate for Anaerobic co-Digestion (AcoD) with Organic Fraction Municipal Solid Waste (OFMSW), (ii) the use of MCW derived activated carbons (ACs) in a H2S removal unit, and (iii) the biogas upgrading to biomethane in a Pressure Swing Adsorption unit. The main aim was to compare the environmental benefits obtained from distinct uses of biogas, specifically the cogeneration of electricity/heat and biomethane production.Three biogas production configurations were considered: (i) AD of standalone hydrolysed OFMSW (hOFMSW); (ii) AcoD of hOFMSW and MCW pre-treated with H2O2 (hOFMSW + PreMCW); and (iii) AcoD of hOFMSW with non-pre-treated MCW (hOFMSW + MCW). The increase of biogas and methane yields obtained with AcoD of hOFMSW + MCW provided an overall better environmental performance than other configurations. With this configuration the FRS, MRS and GW (hh) categories of impacts provided values of 3.12E-02 and -2.49E-05 US$2013, and 4.87E-09 DALY, respectively, that are 47%, 15% and 97% lower than the corresponding value obtained with AD of standalone OFMSW.The biogas upgrading to biomethane from AcoD of hOFMSW + MCW generated higher environmental impacts than cogeneration, due to the AC production and upgrading processes. If an optimised H2S adsorption capacity is considered, the Fossil Resource Scarcity, Mineral Resource Scarcity, and Global Warming human health impact categories decreased by 20%, 15%, and 17%, respectively, when compared to the base-case upgrading scenario. Further decreases of up to 52%, 23%, and 28% for those impact categories, respectively, are observed when the natural gas used in the OFMSW collection and transportation fleet is substituted by biomethane produced in the biorefinery.

Application of Sugar Beet Pulp Digestate as a Soil Amendment in the Production of Energy Maize

This study aimed to determine the suitability of sugar beet pulp digestion by-products as soil amendments for maize grown for energy purposes. In a plot experiment, nitrogen fertilizer at a standard rate of 200 kg N ha−1 was applied as a control vs. treatment with solid and liquid digestate fractions. Digestate was obtained from a gasifier processing only sugar beet pulp. Following harvest, heating and calorific values were determined together with the yield and chemical composition of the maize cob and stover. It was found that soil amendment with crude (unseparated) digestate or its two fractions (separated into liquid and solid) produced higher yields of maize cobs and stover compared with the application of standard fertilizer. An analysis of the energy value of the maize plant revealed differences between the studied soil treatments. Cobs obtained from plots treated with the digestate showed higher calorific and heating values than those obtained from control plots; however, maize stover from control plots showed higher calorific and heating values compared with plants from other experimental plots. It can be concluded that by-products obtained from sugar beet pulp digestion can be alternatively used as a soil amendment for maize production in a crop rotation with sugar beet. Among studied amendments the solid fraction of the digestate was found to have the best performance.

Utilization of Agro-Waste in the Elimination of Dyes from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies

The prospective of maize cob powder (MCP) as an effective adsorbent for the removal of malachite green (MG) and congo red (CR) dyes from aqueous solution was investigated. The presence of functional groups and pores on maize cob powder were confirmed by FTIR and SEM analysis. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were examined to observe their effects in the dyes adsorption process. The optimum conditions for the adsorption of MG and CR onto the adsorbent (MCP) was found to be: contact time (60mins), pH (10.0) and temperature (303 K), adsorbent dose (1 g) for an initial MG dye concentration of 50 mg/L and contact time (80mins), pH (2.0) and temperature (343 K) for an initial CR dye concentration of 50 mg/L and adsorbent dose 1.0 g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for CR dye adsorption and Langmuir Isotherm for MG adsorption. The maximum adsorption capacity was found to be 13.02 mg/g and 9.41 mg/g for the adsorption of MG and CR dyes respectively. The kinetic data conformed to the pseudo-second-order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were evaluated and the negative values of ΔG0, ΔH0 and ΔS0 obtained indicated the spontaneous and exothermic nature of the MG adsorption process while positive enthalpy (ΔH0) indicated an endothermic nature of CR adsorption process.

On-farm seed priming with zinc nutrition: a cost effective way to increase the yield of resource poor farmers

Among the micronutrients, Zinc (Zn) is one of the essential nutrient due to its involvement in many metabolic processes in plant. The research was conducted to optimize Zn seed priming treatments for improving the yield attributing traits and crop yield of pea and maize crops. Different priming levels of Zn (water soaking- without zinc, 1%, 2% and 3% ZnSO4), were applied with three priming durations (4, 8 and 12 hours). The priming treatments were compared with basal dose of recommended NPK + ZnSO4 @ 25 kg ha−1 and farmers’ practice (40% N of RDF + unprimed seed- control). The results showed that seed priming with 1% ZnSO4 for 12 hours solution increased yield attributing traits (length of pea pods, number of pods/plant, number of grains/pod and shelling in pea pods) and yield of green peas, however in maize crop yield attributing traits (length of maize cobs, number of cobs/plant, number of grains/cob, shelling in maize cobs, girth of maize cobs and 1000-grain weight of maize) and yield were found maximum due to priming with 2% for 12 hours duration.

Lignocellulolytic activity of Pleurotus ostreatus under solid state fermentation using silage, stover, and cobs of maize

Lignocellulolytic white-rot fungi allow the bioconversion of agricultural wastes into value-added products that are used in a myriad of applications. The aim of this work was to use corn residues (Zea mays L.) to produce valuable products under solid-state fermentation (SSF) with Pleurotus ostreatus. White-rot fungus P. ostreatus was isolated from maize silage (MS) and thereafter it was inoculated on MS as substrate and compared with maize stover (MSt) and maize cobs (MC) to determine the best lignocellulosic substrate for the production of lignocellulolytic enzymes and extracellular protein. The MS gave the highest productivity of CMCase (368.2 U/mL), FPase (170.5 U/mL), laccase (11.4 U/mL), and MnPase (6.6 U/mL). This is compared to productivity on MSt of 222 U/mL, 50.2 U/mL, 4.55 U/mL, and 2.57 U/mL, respectively; and productivity on MC at the same incubation period as 150.5 U/mL, 48.2 U/mL, 3.58 U/mL, and 2.5 U/mL, respectively. The levels of enzyme production declined with increasing incubation period after 15 and 20 days using MS and MC, respectively, as substrates. Maximum liberated extracellular protein content (754 to 878 µg/mL) was recorded using MS, while a low amount (343 to 408 µg/mL) was liberated with using MSt and MC.

Utilization of Agro-Waste in the Elimination of Dyes from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies

The prospective of maize cob powder (MCP) as an effective adsorbent for the removal of malachite green (MG) and congo red (CR) dyes from aqueous solution was investigated. The presence of functional groups and pores on maize cob powder were confirmed by FTIR and SEM analysis. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were examined to observe their effects in the dyes adsorption process. The optimum conditions for the adsorption of MG and CR onto the adsorbent (MCP) was found to be: contact time (60mins), pH (10.0) and temperature (303 K), adsorbent dose (1 g) for an initial MG dye concentration of 50 mg/L and contact time (80mins), pH (2.0) and temperature (343 K) for an initial CR dye concentration of 50 mg/L and adsorbent dose 1.0 g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for CR dye adsorption and Langmuir Isotherm for MG adsorption. The maximum adsorption capacity was found to be 13.02 mg/g and 9.41 mg/g for the adsorption of MG and CR dyes respectively. The kinetic data conformed to the pseudo-second-order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were evaluated and the negative values of ΔG0, ΔH0 and ΔS0 obtained indicated the spontaneous and exothermic nature of the MG adsorption process while positive enthalpy (ΔH0) indicated an endothermic nature of CR adsorption process.

English

Previous proteomic studies have shown maize cob tissue to have an essential role in pathogen defense. Currently, there are no studies published regarding neither maize cob metabolomic profiles nor an accepted method of metabolite extraction from cob. This study assesses the reproducibility of metabolite extraction from the cobs of fungal pathogen -resistant and -susceptible cultivars. Hand grinding, mechanical ball-milling and adapted focused acoustics methods of tissue homogenization were preformed and examined via Liquid Chromatography-Mass Spectrometry (LC-MS). Among tested methods, the manual grinding with a mortar and pestle was found to be the most reproducible and efficient. All methods showed good reproducibility within but provided statistically different sets of metabolite features when compared across methods. A suitable extraction method for future cob metabolomics experiments was ascertained, however careful results validation will be needed to distinguish between true biological phenomenon and artifacts rising from a methodology bias. For the first time, maize cob metabolites have been successfully extracted and detected, establishing a reproducible method for further metabolomic profiling of cob defense metabolites.   Key words: Liquid Chromatography-Mass Spectrometry (LC-MS), metabolomics, Aspergillus flavus, homogenization, extraction, grinding.

Performance evaluation of throat type updraft biomass gasifier using different biomass fuels

A biomass gasifier converts solid fuel such as wood waste, saw-dust briquettes and agro-residues into a gaseous fuel through a thermo-chemical process and the resultant gas can be used for thermal and power generation applications. The present research aims to evaluate the updraft biomass gasifier using different biomass for thermal application. The capacity of updraft gasifier was a 5-10 kg.h-1 and three types of biomass: maize cobs, sized wood and saw dust briquettes were used as fuel for producing producer gas by thermal application. The maximum carbon monoxide (CO), hydrogen (H2) and Methane (CH4) found were 14.8, 12.7 and 3.9%, 14.6, 13.7 and 3.9 % and 14.2, 13.5 and 3.9% at 5 kg.h-1 biomass consumption rate, respectively using maize cobs, sized wood and saw dust briquettes as fuel. The maximum and minimum producer gas calorific value was found 1120 and 1034 kcal.m-3; 1139 and 1034 kcal.m-3 and 1123 and 1036 kcal.m-3 at biomass consumption rate of 5 and 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel respectively. The maximum gasifier efficiency of 77.94, 70.26 and 69.60% was found at the biomass consumption rate of 5 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel, respectively. The minimum gasifier efficiency of 72.72, 64.49 and 64.90 % was found at the biomass consumption rate of 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel in the system, respectively. The maximum overall thermal efficiency of 29.60, 30.65 and 23.69 % were found at the biomass consumption rates of 8, 7 and 7 kg.h-1 using maize cobs, sized wood and saw dust briquettes, respectively.

Adsorption Equilibrium, Physicochemical Parameters and Colour Deactivation Effects of Activated Carbon for Dye for Waste Water Treatment

Effluents from dye and dyeing industries constitute serious environmental threat and attracting serious attention. Activated carbon prepared from guinea corn husk and maize cobs waste materials was used as a precursor to prepare activated carbon. Variable ratios of the constituent ashes ( 1:1, 1:3 and 3:1) were prepared. The husk and cobs were ashed in a murfle furnace at 400-500oC for 2.5 h. Acid activation was carried out by washing with HCl (1M) after which it was characterized using XRF which revealed (in variable proportions) the presence of SiO2, Al2O3 and Fe2O3 as dominant oxides in the ashes. Waste water decolourization efficiency of the adsorbents was tested using dye waste water at same contact time using variable absorbent dosage. Higher moisture (96.80±0.56), Ash (12.90±0.35), pH (6.3±0.17), Conductivity (208±1.34) and Bulk density (12.27±0.61) were obtained for guinea corn husk. The best clearity was obtained after batch adsorption experiments at 1:1 which gave the highest adsorption at equilibrium (Qe) of 28.55 compared to 12.750 and 10.900 obtained for 1;3 and 3:1 respectively.

Concentrations of zearalenone and its metabolites in female wild boars from woodlands and farmlands

As a valuable food base and safe shelter, large agricultural fields create favourable living conditions for wild boars for most of the year. The occurrence of mould in these fields, causing hormonal disturbances, may lead to a lower age of sexual maturity and a prolonged breeding season, and therefore, the population growth in farmlands can be markedly higher than that in extensive woodlands. This study was initiated because of reproductive cycle disturbances in wild boar populations, which were presumably linked with habitat and food types, especially rotten maize. To determine if the major sources of zearalenone (ZEN) in female wild boars are maize cobs infected with mycotoxins, we compared the concentrations of ZEN and its metabolites in organs, tissues and body fluids of wild boars hunted in extensive maize fields and in extensive woodlands where no large maize fields were located within a distance of several km. Samples of blood, bile, liver, kidneys, muscles, urine, stomach and colon contents as well as ovaries from young female wild boars (40–60 kg) were collected in 2011–2014 and prepared for liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results showed that ZEN was present in most of the samples, from both farmlands and woodlands, but its concentration within individual types of the analysed body fluids or tissues differed depending mainly on habitat type. In nearly all the analysed cases, higher concentrations of ZEN and its derivatives were detected in the samples collected from wild boars in farmlands, suggesting that wild boars living and feeding in extensive maize fields take in markedly higher amounts of mycoestrogens.

Blood chemistry of West African dwarf goats fed treated maize cob- and maize husk-based diets with mixture of microorganisms

BackgroundTwenty-four West African Dwarf (WAD) goats with average weight of 6.57 ± 0.56 kg were used in investigating the effect of microbial-treated maize cob and husk diets on blood profile. The goats were assigned to six dietary treatments replicated four times in a completely randomized design. Chopped maize cobs and husks were sterilized for 60 min to eliminate any form of contamination and then inoculated with mixture of 15 ml each of Lactobacillus delbrueckii and Neurospora crassa and incubated anaerobically for 5 days and then air-dried. The treated maize cob and husk were incorporated in the diets at the rate of 0% (diet), 20% (diet B), 30% (diet C) [maize cob diets], and 0% (diet D), 20% (diet E), 30% (diet F) [maize husk diets], respectively. The animals were acclimatized for two weeks while the experimental period lasted for 56 days. A completely randomized design was adopted.ResultsThe results showed that the dietary treatments significantly (P < 0.05) influenced the erythrocyte sedimentation rate which ranged from 0.50 to 1.00 mm/hr. Significant (P < 0.05) differences were observed in the globulin (28.16 g/dl diet A—59.26 g/dl diet B), aspartate aminotransferase (48.00 u/l diet E—128. 25 u/l diet C) and alanine aminotransferase (8.20 u/l diet A—33.33 u/l diet D). Serum electrolytes values were significantly (P < 0.05) influenced by dietary treatments.ConclusionBased on the findings of this study, microbial-treated maize cob and husk diets supported erythropoiesis did not induce any liver damage and the serum electrolytes of the animals were improved. Hence, microbial-treated maize cob and husk can be a suitable alternative feed source at 30% incorporation in a complete diet for WAD goats as adverse implications on the health of the animals was not observed.

Investigation of municipal wastewater treatment by agricultural waste materials in locally designed trickling filter for peri-urban agriculture

Abstract A pilot scale trickling filter system was designed, developed, and operated using a constant recirculation method for treatment of municipal wastewater. Maize cob (TF1) and date palm fibre (TF2) were used as biofilm support media in a trickling filter system. Both the TF1 and TF2 were compared based on the removal efficiency of pollution indicators such as biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), electrical conductivity (EC), total nitrogen (TN), total phosphorus (TP) and sulphates. The hydraulic flow rate and loading were set as 0.432 m3/h and 0.0064 m3/m2.minute, respectively at temperature range of 15–42 °C for 15 operational weeks. Both the TF1 and TF2 showed acceptable removal efficiency (61% to 76.3%) for pathogen indicators such as total count, fecal coliforms and Escherichia coli. However, 8–15% higher removal efficiency was observed for TF1 for all the pollution indicators compared to TF2. The results suggest that both the biofilm support media in trickling filter have potential to treat municipal wastewater in peri-urban small communities to produce environmentally friendly effluent.

Enhanced contaminant removal from municipal wastewater using novel cascade cum trickling filter and multilayer adsorption bioreactor

The novel two-stage treatment system consisting of cascade cum trickling filter (CCTF) and multilayer adsorption (MLA) bioreactor was developed to enhance the contaminants removal such as chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP). The maize cob and date palm fiber were used as biofilm support media in trickling filter. The MLA bioreactor was operated using the composite adsorbent (refused crushed brick + rice husk + steel slags). The maximum adsorption uptake of composite adsorbent was observed as 0.6 mg/g for ammonium and 3.5 mg/g for phosphorus. Kinetic analysis showed that the composite adsorbent had a faster removal rate for phosphate than ammonium. The maximum desorption of ammonium and phosphate was found to be 14.6% and 6.5%, respectively. The performance of both cascade cum trickling filter and multilayer adsorption (CCTF-MLA) systems was also evaluated using the various COD-TN ratios and flow rates. The removal efficiencies of COD, TN and TP were found 93%, 87% and 86%, respectively, and their corresponding mean effluent concentrations were noted 18 mg/L, 5.5 mg/L and 2.3 mg/L. The developed CCTF-MLA system removed the 3log of the total count and total coliform and 2log of Escherichia coli and salmonella. So, the CCTF-MLA system could be efficient for wastewater treatment due to the steady removal rate of COD, TN and TP.

Physical properties of shelled maize (Zea mays L.) cobs

Gasification is an effective technology for the formation of producer gas from biomass with least greenhouse gas emissions. The aim of this investigation was to analyze the physical properties of shelled maize cobs. The length, moisture content and bulk density of maize cobs were determined as per the standard procedure. It was found that range of length, moisture content and bulk density of maize cobs was suitable for being used in a downdraft gasifier.

Physico-Mechanical Properties of Cement-Bonded Boards Produced from Mixture of Corn Cob Particles and Gmelina arborea Sawdust

Cement bonded boards of 10 mm in thickness were produced from the mixture of Gmelina arborea sawdust and corn cob particles. The strength and dimensional stability of cement bonded composites produced from these two mixtures were examined. A total of thirty experimental boards were produced at density level of 1,000 kg/m3 with cement to fibre ratio of 2.5:1 and 3:1 and five (5) blending proportions of G. arborea sawdust to corn cob particles of 100:0; 75:25; 50:50; 25:75 and 100:0. The effect of the cement to fibre ratio and blending proportion on the Water Absorption (WA), Thickness Swelling (TS), Modulus of Rupture (MOR), and Modulus of Elasticity (MOE) were determined. The result indicates that as the mixing ratio of cement to fibre and blending proportion of maize cob (75%) to G. arborea (25%) increased, the thickness swelling, water absorption decreased, whereas the MOR and MOE increased. It also shows that most dimensionally stable and flexural strength boards were produced at the highest level of mixing ratios (3:1) and blending proportion of G. arborea to corn cob 25:75. However, the analysis of variance shows that TS and WA were significantly different, whereas, MOE and MOR were not significantly affected by mixing ratios and blending proportions. Finding of this study has shown that maize cob particles are suitable for cement bonded board production.

Performance Evaluation of a Forced Convection Mixed Mode Solar Grain Dryer with a Preheater

In this study the performance of a forced convection mixed-mode solar grain dryer integrated with a preheater was evaluated. The type of grains used in the experiment were 72 freshly harvested maize cobs with a total mass of 17 kg. The experiment was conducted at various airflow speeds and preheater temperatures ranging from 0.5 m/s to 2 m/s and 30 ℃ to 40 ℃, respectively. The aim of the study was to improve the performance of an existing indirect solar dryer which was converted to a mixed-mode solar dryer. The initial thermal efficiency of the indirect solar dryer before modification was 36 %. The results from the experiment indicated a maximum thermal efficiency of 58.8 % with a corresponding drying rate of 0.0438 kg/hr. The minimum thermal efficiency for the mixed-mode solar grain dryer system was 47.7 %, with a corresponding drying rate of 0.0356 kg/hr. The fastest drying time of maize cobs was achieved in 4 hours and 34 minutes from an initial moisture content of 24.7 % wb to 12.5 % wb. The findings show a significant improvement in the dryer system’s performance. This is a clear indication that operating a solar dryer system in mixed-mode operation with forced convection and the assistance of a preheater or backup heater can significantly improve drying processes and increase food preservation.

Evaluating the Suitability of Baobab Fruit Shells as Substrate for Growing Oyster Mushroom (Pleurotus ostreatus)

The baobab fruit shells were evaluated for their suitability as a substrate for growing oyster mushrooms and compared to three base substrates (wheat straw, maize cobs, and sawdust) of 1 kg dry weight. The duration of developmental stages, mycelium vigor, yield, and biological efficiency of the oyster mushroom from the four different substrates were recorded. Yields from the first 3 harvests (flushes) were considered, as they were the most productive ones. Wheat straw demonstrated significantly ( p &lt; 0.05 ) higher mycelial colonization rate taking an average of 23 days to complete full spawn run followed by baobab fruit shells, sawdust, and maize cobs which took averages of 25.8, 27.2, and 29.5 days, respectively. Baobab fruit shells had the longest number of days taken between full spawn run and first pinhead formation with an average of 14.4 days which was significantly different ( p &lt; 0.05 ) to the wheat straw, sawdust, and maize cobs which had 7.4, 9.4, and 10.5 days. The highest yield was observed on the sawdust which had an average of 682 g followed by wheat straw with 594 g. Maize cobs and baobab fruit shells had the least yield of 518 g and 482 g, respectively. The results showed that baobab fruit shells could be used as a substrate for the cultivation of oyster mushrooms and it can be recommended for commercial cultivation of oyster mushrooms.