EFFECT OF SOME AGRO-INDUSTRIAL RESIDUES ON MYCELIAL GROWTH AND PRODUCTION OF LIGNOCELLULOLYTIC ENZYMES BY A FUNGUS NATIVE TO ALGERIAN FOREST

Valorization of agricultural and agro-food by-products by fermentation constitutes a very interesting biotechnological approach for the production of lignocellulolytic enzymes. This work was carried out to reveal the effect of some lignocellulosic materials on the mycelial growth and lignocellulolytic enzymes production by Bjerkandera adusta BRFM 1916. The strain showed ABTS- and guaiacol-oxidation activities. The optimal temperature for mycelial growth was 28 °C. The maximum growth rate of this fungus was achieved on wheat bran (2.08 ± 0.05 cm day-1), followed by barley bran, with a significant reduction of 6.73%. Several agricultural lignocellulosic residues were used as substrates for enzymes production. All the data indicated differential utilization of the various materials by the fungus. The selected fungus produced good CMCase (690 ± 0.066 UL-1) and β-Glu (253 UL-1) activities on wheat bran and orange peels, respectively. A high level of MnP activity (449.21 ± 3.44 UL-1) was obtained on wheat bran.

Utilizing a novel fungal enzymatic cocktail as an eco-friendly alternative for cellulose pulp biobleaching

Enzyme cocktails can alter the lignin and hemicellulose content in wood cell walls, improving the bleaching process during pulp production and offsetting the need for toxic chemicals. In this study, brown pulp was biobleached with a mixture of crude fungal extracts rich in xylanase and laccase, respectively produced from Aspergillus tamarii Kita and Trametes versicolor on waste materials. The optimal conditions for biobleaching were a mixture of xylanase and laccase crude extracts (1 to 2 v/v), at a temperature of 36 °C and a pH of 5.5. The treated brown cellulose pulp showed a reduction in the Kappa number by 1.83 points, representing an efficiency of 20.3%. In addition, the brightness increased by 4.65 points in comparison to the control. Hence, studies involving the application of the standardized cocktail during the hydrolysis of lignocellulosic residues, e.g., barley residue and sugarcane bagasse, led to the formation of 85 g/L and 25 g/L of reducing sugars, respectively. Moreover, the standardized cocktail caused greater deinking of the recycled paper pulp.

El Papel de los Residuos Agrícolas en la Extracción de Nanocristales de Celulosa

El objetivo del presente estudio fue revisar fuentes documentales sobre el contenido lignocelulósico de los residuos agrícolas del cultivo de arroz, plátano, maíz, caña de azúcar, y piña para la obtención de nanocristales de celulosa. La investigación con enfoque cualitativo- documental descriptivo recopiló datos del objeto de estudio para su análisis y evaluación. Se analizaron diversos planteamientos teóricos, procedimentales y metodológicos para la obtención de nanocristales de celulosa; se identificó el tipo de residuo generado por cada cultivo en estudio, de los cuales se describió el contenido lignocelulósico que poseen con el propósito de establecer que por su composición se constituyen en un material potencial para la obtención de nanocelulosa; luego se analizaron los métodos empleados en la obtención de nanocristales de celulosa. Con base a los documentos revisados se concluye que los diferentes residuos agrícolas poseen un contenido celulósico relevante (28-100%), por tanto, convirtiéndolos en materiales aptos para ser aprovechados para obtener nanocristales de celulosa. Palabra clave: Hidrólisis ácida, métodos de extracción, residuos lignocelulósicos. Abstract The objective of this study was to review documentary sources on the lignocellulosic content of agricultural residues from the cultivation of rice, banana, corn, sugar cane, and pineapple to obtain cellulose nanocrystals. Research with a qualitative - documentary and descriptive approach, collected data from the object of study for analysis and evaluation. Various theoretical, procedural, and methodological approaches for obtaining cellulose nanocrystals were analyzed; the type of residue generated by each culture under study was identified, of which the lignocellulosic content that they possess was described, In order to establish that their composition constitutes a potential material for obtaining nanocellulose, the methods used in obtaining cellulose nanocrystals were then analyzed. Based on the revised documents, it is concluded that the different agricultural residues have a relevant cellulosic content (28-100%), therefore, converting them into materials suitable to be used to obtain cellulose nanocrystals. Keywords: Acid hydrolysis, extraction methods, lignocellulosic residues.

Alkaline pretreatment and enzymatic hydrolysis of corn stover for bioethanol production

The demand for ethanol in Brazil is growing. However, although the country is one of the largest producers of this fuel, it is still necessary to diversify the production matrix. In that regard, studies with different raw materials are needed, mainly the use of low cost and high available wastes such as lignocellulosic residues from agriculture. Therefore, this study aimed to analyze the bioethanol production from corn stover. An alkaline pretreatment (CaO) was carried out, followed by enzymatic hydrolysis (Cellic Ctec2 and Cellic Htec2) to obtain fermentable sugars. The best experimental condition for the pretreatment and hydrolysis steps resulted in a solution with 0.31 gsugar∙gbiomass-1. Then, the fermentation was performed by the industrial strain of Saccharomyces cerevisiae (PE-2) and by the wild yeast strain Wickerhamomyces sp. (UFFS-CE-3.1.2). The yield obtained was 0.38 gethanol∙gdry biomass-1 was, demonstrating the potential of this process for bioethanol production.

Determination of the Optimal Size and Location of an Electricity Generation Plant That Uses Lignocellulosic Residues From Costa Rican Northern

The northern zone of Costa Rica has extensive forestry and agro-industrial development, which generates a large number of lignocellulosic residues that do not have an economic value but could represent a vast energy potential. Therefore, the objective of this study was to determine the optimal size and location of an electricity generation plant from the forest and agro-industrial biomass. The researchers worked with two forest species residues (Gmelina arborea and Tectona grandis) and two agro-industrial residues (Anana comosus and Saccharum officinarum), representing the most extensive cultivations in the region. The material was characterized, then GIS layers of the species cultivation areas were analyzed and related to the roads and protected areas to define the twelve potential points where the power plant should be installed. Later the optimal supply radius of the plant and the optimal site conditions were determined. The study determined that the tree species have an average caloric power of 19059.50 kJ/kg, significantly higher than the agro-industrial ones (16684.9 kJ/kg). It was determined that 1,056,527.67 tons of dry biomass are generated per year, 6.5% of the biomass is arboreal, and 79.97% comes from A. comosus. Also, it was determined that the optimal supply radius for the plant is 30 km. Longer distances make the project financially unviable. Considering this, the annual energy potential of the twelve points was evaluated, which varied from 4.06 to 101.82 MW. Point eleven was determined the best positioned by the biomass source and optimal environmental conditions for establishing the power plant.