Potentials of rice husk ash for soil stabilization

Due to the large production of agricultural wastes, the world is facing a serious problem of its handling and disposal. The disposal of agricultural wastes has a potential negative impact on the environment causing air pollution, water pollution and finally affecting the local ecosystems. So it is mandatory to make these agricultural wastes eco- friendly. By using them as soil stabilizers, these agricultural wastes improves the strength of soil and its characteristics without causing any harm to the environment

Agricultural Waste as Raw Materials for the Production of Activated Carbon: Can Tanzania Venture into this Business?

Activated Carbon (AC) can be produced from a variety of carbonaceous materials. Traditionally, they are produced from coal, lignite, coconut shells and wood peat thus raising the cost of commercial activated carbons. Agricultural wastes and by-products are considered good alternative source materials for production of activated carbons because of their abundance, high carbon content and cheap availability. In this review, an extensive list of agricultural wastes and by-products from vast literature has been assessed and properties of activated carbons produced from them evaluated. The potential of Tanzanian agricultural wastes for production of activated carbons is also discussed. Among the variety of agricultural wastes studied, nut shells, stones, seed hulls/husks, plant straws/stalks, sugar cane bagasse and agro-forestry residues such as sawdust have drawn much interest. The review also reveals that indeed agricultural wastes can produce activated carbons with properties comparable to commercial ones. In this case, Tanzania stands a chance of benefitting both economically and environmentally if it utilises the agrowastes for large scale production of activated carbons.Keywords: Activated carbons, physical activation, chemical activation, agricultural wastes

Vicia faba Crop Residues for Sustainable Electricity Generation Using a Sludge-based Microbial Fuel Cell

Microbial fuel cells (MFC) simultaneously degrade organic substrates and generate electricity in a sustainable and eco-friendly way. Here, we built a 4-unit MFC and studied the efficiency of MFC at different conditions, including pH, substrate concentration of Vicia faba agricultural wastes with exoelectrogenic bacteria P. aeruginosa. The exoelectrogenic bacteria were obtained from industrial effluents and used to inoculate the MFCs. The optimized conditions in terms of yielding maximum potential of 802 mV, yielding maximum power density of 283 mW m–2 were reported at a substrate concentration of 6 g L–1 of V. faba waste and pH of 5.5, corresponding to a current density 1255.93 mA m–2. Using exoelectrogenic bacteria from industrial effluents and agricultural wastes resulted in efficient MFC. Thus, the developed MFCs using V. faba agricultural wastes can be used in rural areas that have limited access to electricity, by reusing agricultural wastes and concomitant electricity generation. This work is licensed under a Creative Commons Attribution 4.0 International License

Effect of wheat bran supplementation with fresh and composted agricultural wastes on the growth of Kenyan native wood ear mushrooms [Auricularia auricula (L. ex Hook.) Underw.]

Nutrient supplements and agricultural wastes used for mushroom cultivation are important in improving establishment and production of mushrooms. Agricultural wastes such as sawdust, grass, sugarcane bagasse, wheat straw and maize cobs have successfully been used for the production of Kenyan wood ear mushrooms [Auricularia auricula (L. ex Hook.) Underw.]. However, the effect of varying concentrations of wheat bran supplements on their productivity has not been fully researched. In this study, fresh and composted agricultural wastes were supplemented with wheat bran at concentrations of 0, 5, 10 and 20%. The cultivation experiment was arranged in a completely randomized design (CRD) and replicated three times. Data was collected on days to spawn run, days to primordial initiation, primordial concentration quality and biological efficiency. The data collected was subjected to analysis of variance using SAS version 9.1. Mean separation was done using least significant difference (LSD) and effects were declared significant at 5% level. Key words: Wood ear mushrooms, fresh and composted agricultural wastes, wheat bran, Kenya

Effect of wheat bran supplementation with fresh and composted agricultural wastes on the growth of Kenyan native wood ear mushrooms [Auricularia auricula (L. ex Hook.) Underw.]

Nutrient supplements and agricultural wastes used for mushroom cultivation are important in improving establishment and production of mushrooms. Agricultural wastes such as sawdust, grass, sugarcane bagasse, wheat straw and maize cobs have successfully been used for the production of Kenyan wood ear mushrooms [Auricularia auricula (L. ex Hook.) Underw.]. However, the effect of varying concentrations of wheat bran supplements on their productivity has not been fully researched. In this study, fresh and composted agricultural wastes were supplemented with wheat bran at concentrations of 0, 5, 10 and 20%. The cultivation experiment was arranged in a completely randomized design (CRD) and replicated three times. Data was collected on days to spawn run, days to primordial initiation, primordial concentration quality and biological efficiency. The data collected was subjected to analysis of variance using SAS version 9.1. Mean separation was done using least significant difference (LSD) and effects were declared significant at 5% level.Keywords: Wood ear mushrooms, fresh and composted agricultural wastes, wheat bran, KenyaAfrican Journal of Biotechnology Vol. 12(19), pp. 2692-269

Bioethanol production from agricultural wastes

In this study, different strains of Saccharomyces cerevisiae have been screened for the ability of bioethanol production. Yeasts were grown in synthetic liquid medium containing two different substrates: sucrose at different concentrations (10 to 400g/l) and cane molasses (120g/l of sucrose). The screening was made in batch regime and the growth rates, ethanol and biomass productions were determined. The results indicate a flocculent yeast strain – F as the more suitable microorganism to produce ethanol, presenting the highest value of growth rate (0.49h-1) and ethanol yield (0.40g/g) with 120g/l of sucrose concentration. In addition, ethanol production was also studied in a continuous process with the selected yeast strain (F strain), with sucrose and cane molasses (120g/l) at different dilution rates (0.05-0.5 h-1). Data showed that when dilution rate raised to 0.4h-1 the highest sugar conversion, 85% and 90%, were achieved with an ethanol production of 40.5g/l and 50.8g/l for sucrose and molasses, respectively

Temporal variations in organic carbon, soil reactivity and aggregate stability in soils of contrasting cropping history

We studied the effect of incorporating agricultural wastes on soil aggregate stability (AS), organic carbon (OC), and soil reactivity (pH) of similarly textured soils under different managements (vegetable,(VG) and Orchard (OR) farming), in South-eastern Nigeria. The agricultural wastes were cow dung (CD,) cassava peels (CP), and kola nut pods (KP). The air dried agricultural wastes were crushed and sieved using a 2 mm wire mesh and decomposed under shade for two weeks. The decomposed amendments were applied in combination (CD+CP, CD+KP), or alone (KP, CP, CD) at the rates of 100 and 200 Mg/ha. Samples for physical and chemical analysis were collected in triplicate after two and four weeks of incubation and analyzed for selected physiochemical properties. Results show that combinations ofwastes of plant and animal origin (CD+CP or CD+KP) enhanced the soil properties better than their single applications. The immediate effect of agricultural wastes in improving the pH (20-40 or 30-50%,respectively, for vegetable and orchard farm management) gave corresponding increases in organic carbon and soil aggregate stability and suggested that decomposition of agricultural wastes prior toincorporation is necessary to sustain vegetable or orchard farming. Significant positive correlation coefficients of 0.893 and 0.911 for the first and second sampling times indicated that organic carbonaccounted for 79.7 and 83% of the soil aggregate stability at both periods. For the vegetable farm, 70% of soil aggregate stability depended on the level of organic carbon while about 87% of soil aggregate stability is accounted for in the Orchard farm by organic carbon

Designing a New Cement Composition Using Agricultural Wastes for Underground Gas Storage

To reinforce cement against the attack of supercritical CO2 in a storage site, agricultural wastes (POFA and RHA) and Nano particles (Nano Silica) were used. Post-carbonation tests of agricultural wastes and Nano Silica based cement were done according to the API standard and it was found that almost all samples have a lesser carbonated area then the neat cement except 5 wt% POFA. Nano Silica based cement seem to be the best choice

Antagonistic capacities of Trichoderma species and their mass multiplication with agricultural wastes

El objetivo de esta investigación fue aislar y caracterizar cepas de Trichoderma nativas de Misiones (Argentina)explorando sus capacidades antagónicas y su multiplicación masiva utilizando diferentes residuos agroindustriales.Quince cepas nativas de Trichoderma spp. fueron aisladas de muestras de suelo. Estos aislamientos secaracterizaron mediante observaciones morfológicas y moleculares basados en secuencias de ADN de la regiónespaciadora transcrita interna del ADNr. Las cepas de Trichoderma spp. fueron identificadas como T. koningiopsis,T. harzianum, T. pleuroticola y T. brevicompactum. Estas cepas mostraron actividades antagónicas in vitro contraAlternaria sp., Fusarium sp. y Botrytis sp.. T. koningiopsis LBM 090, LBM 091, LBM 092 y LBM 098, T. pleuroticolaLBM 097 y T. harzianum LBM 096 presentaron una inhibición del crecimiento micelial mayor del 50% y un índicede antagonismo entre 3 y 4 contra los fitopatógenos ensayados. La cáscara de arroz y el pulido del arroz fueronlas combinaciones más adecuadas para la multiplicación de T. harzianum LBM 096.The aim of this research was to isolate and characterize Trichoderma native strains from Misiones (Argentina) exploring their antagonistic capacities to phytopatogens fungi and their mass multiplication using different agricultural wastes. Fifteen native strains of Trichoderma spp. were isolated from soil samples. These isolates were characterized via morphological observations and molecular phylogenetic analysis based on DNA sequences of the rDNA internal transcribed spacer region. The Trichoderma native strains were identified as T. koningiopsis, T. harzianum, T. pleuroticola and T. brevicompactum. All strains showed antagonistic activities in vitro against Alternaria sp., Fusarium sp. and Botrytis sp. T. koningiopsis LBM 090, LBM 091, LBM 092, and LBM 098 strains, T. pleuroticola LBM 097 and T. harzianum LBM 096 presented radial mycelial growth inhibition higher than 50% and antagonism index between 3 and 4 against the phytopathogens assayed. Among the different substrate sources evaluated, rice husk and rice polishing were the most suitable combination for mass multiplication of T. harzianum LBM 096.Fil: Sadañoski, Marcela Alejandra. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Gutierrez Brower, Gimena. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Castrillo, María Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Lopez, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Ojeda, Paola. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Zapata, Pedro Dario. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Villalba, Laura Lidia. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Otegui, Monica Beatriz. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentin

Dry Anaerobic Digestion for Agricultural Waste Recycling

For sustainable agriculture, it is important to manage agricultural wastes, such as crop residues and livestock wastes. Anaerobic digestion has been gathering the attention to recycle these wastes into renewable energy (biogas) and fertilizer (soil amendment) (digestate). Dry anaerobic digestion is defined as digestion at higher than 20% of total solid (TS) content in the reactor, which is suitable for wastes with high TS content, such as agricultural wastes. In this chapter, we reviewed recent advances in biogas production and use of digestate as soil amendment from dry anaerobic digestion of agricultural wastes. It has been found that ammonia concentration, feed/inoculum (F/I) ratio, and TS content are important parameters for operation of dry anaerobic digestion. Several operation technologies have been in operation, while new operation strategies have been developed. Application of solid digestate into the soil is beneficial to increase soil properties; however it should be carefully operated because it has risks of nitrate leaching and soil pathogens