RESUMO

Lignocellulosic biomass conversion applying thermochemical routes has been postulated as an alternative for generating renewable energy. This research compares energy-driven biorefineries based on two thermochemical routes addressed to upgrade rice husk and rice straw produced in the Department of Sucre-Colombia. Initially, this research analyzes the physico-chemical and structural characterization of the rice residues. Four different scenarios were proposed to compare the energy-driven biorefineries based on fast pyrolysis and gasification considering technical, economic, and environmental metrics. These biorefineries were simulated using the Aspen Plus V.14.0 software. The novelty of this research is focused on the identification of the biorefinery with the best techno-economic, energetic, and environmental performance in the Colombian context. Economic and environmental analyses were done by using economic metrics and emissions. From an economic perspective, the stand-alone gasification process did not have a positive economic margin. In contrast, the fast pyrolysis process has the best economic performance since this process has a positive profit margin. Indeed, scenario 1 (fast pyrolysis of both rice residues) presented an economic margin of 13.75% and emissions of 2170.92 kgCO2eq/kg for 10 years. However, this scenario was not energetically the best, holding second place due to the feedstock requirements, compared to gasification. The biorefinery scenario 1 has the best performance.

RESUMO

To attend to the growing world demand for mushrooms, it is interesting to increase the system's productivity, improve quality and reduce production costs. This study aimed to optimize the production and quality of fruiting bodies of the edible and medicinal mushroom Lentinula edodes (shiitake), in agroresidues substrate using appropriate strain and spawn formulation. The evaluation was conducted using two strains under seven different spawn formulations (Control [C]: Sorghum grain + 2.5% CaCO3; (2) C + 2.5% sawdust; (T3) C + 5% sawdust; (T4) C + 2.5% peat; (T5) C + 5% peat; (T6) C + 1.25% sawdust + 1.25% peat; (T7) C + 2.5% sawdust + 2.5% peat) that were inoculated into the blocks at a proportion of 2% (w/w). The substrate was formulated with 63% rice straw, 20% sawdust, 15% wheat bran, and 2% CaCO3 and sterilized. The incubation period was 87 days. Two flushes were obtained. Adding small aliquots of peat and sawdust to the inoculum gave significantly higher morphological results than the control in all variables analyzed. The days required for the first harvest ranged from 87 to 94 days. The average weight of basidiomes ranged from 6.38 to 28.75 g. The productivity data show superior results for the treatments in which the spawn was supplemented with sawdust and peat. Enhanced bioconversion with supplemented spawn shows promises for yield and composition improvement, crucial for commercial viability. It can be concluded that shiitake production using agroresidues such as straw can be increased using a suitable strain/spawn for optimal production.

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The present work refers to a process involving the use of dilute nitric acid pretreatment and enzymatic hydrolysis for the transformation of rice straw into simple sugars. Acid pre-treated rice straw was separated into the pulp and supernatant through centrifugation and filtration. The two fractions are then converted into simple sugars by combined action of microbes producing cellulase and laccase enzymes. These microbes were isolated from soil samples which were collected from different locations with varying altitudes, expected to harbour microbes with high-hydrolysing activity. The nitric acid pretreatment was carried out at 30 °C, 200 rpm for 72 h. After 72 h, the culture supernatants were analysed for the presence of glucose with the help of HPLC. The supernatant fraction separated after the acid pre-treated rice straw produced highest amount of glucose (205 mg/g of rice straw) upon subsequent hydrolysis with synergistic action of cellulase and laccase-producing microbes.

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Resumen El tamo de arroz es uno de los residuos agrícolas lignocelulósicos más abundantes en el planeta, luego de los residuos producidos por los cultivos de maíz y trigo, con una producción mundial estimada de 1000 millones de toneladas según estadísticas de la FAO. En el contexto de la agricultura moderna es determinante lograr un manejo ambientalmente sostenible de este recurso mediante su incorporación al suelo, de tal forma que se logre el reciclaje de nutrientes, evitando la incorporación de patógenos al sistema y la inmovilización de elementos como el nitrógeno por la comunidad microbiana. El objetivo de este trabajo consistió en la evaluación de un inoculo microbiano mixto a partir de productos comerciales basados en hongos del género Trichoderma y bacterias aerobias formadoras de endosporas, con potencial degradador del tamo de arroz, así como el empleo de bacterias promotoras de crecimiento vegetal al momento de la siembra, que pudieran aprovechar los nutrientes del proceso de descomposición del tamo de arroz, potenciando su actividad biológica. Los tratamientos fueron evaluados bajo diferentes relaciones C:N del tamo de arroz que favorecieran el proceso de degradación, mediante la adición de nitrógeno inorgánico. Los resultados del trabajo permitieron identificar que la aplicación de una enmienda de nitrógeno a una relación C:N 35 más una dosis adicional de urea al momento de la siembra de las semillas de arroz, fue el tratamiento más adecuado para potenciar el efecto de los microorganismos e incrementar las variables agronómicas obtenidas mediante un esquema de fertilización convencional del cultivo.

Abstract Rice straw is one of the most abundant lignocellulosic agricultural residues on the world, after residues produced by maize and wheat crops, with an estimated global production of 1000 million tones according to FAO statistics. In the context of modern agriculture, it is essential to achieve an environmentally sustainable management of this resource, through the incorporation of rice straw into the soil, in order to achieve nutrient recycling avoiding the incorporation of pathogens into the system and the losses of nitrogen due to soil microbial biomass immobilization. In this context, the objective of this work consisted in the evaluation of a mixed microbial inoculum with degrading potential of rice straw from commercial products based on the fungus Trichoderma spp. and aerobic endospore forming bacteria. It was also used a plant growth promoting bacteria at the time of planting, in order to take advantage of nutrients released from RS decomposition and improve its biological activity. These microbial treatments, were evaluated at different concentrations of inorganic nitrogen amendments that allowed different levels of rice straw´s C:N ratio, favoring the degradation process. Overall results allowed to identify that the application of a nitrogen amendment to rice straw up to C:N 35, plus an additional dose of urea at the time of rice seeds planting, was the most adequate treatment to potentiate the effect of the microorganisms and to increase or maintain the agronomic variables obtained through a conventional fertilization management of the crop.

RESUMO

The objective of this study was to evaluate the potential of eight fungal isolates obtained from soils in rice crops for straw degradation in situ. From the initial eight isolates, Pleurotus ostreatus T1.1 and Penicillium sp. HC1 were selected for further characterization based on qualitative cellulolytic enzyme production and capacity to use rice straw as a sole carbon source. Subsequently, cellulolytic, xylanolytic, and lignolytic (Pleurotus ostreatus) activity on carboxymethyl cellulose, oat xylan, and rice straw with different nitrogen sources was evaluated. From the results obtained it was concluded both isolates are capable to produce enzymes necessary for rice straw degradation. However, their production is dependent upon carbon and nitrogen source. Last, it was established that Pleurotus ostreatus T1.1 and Penicillium sp. HC1 capability to colonize and mineralize rice straw, in mono-and co-culture, without affecting nitrogen soil content.

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ABSTRACT: Ensilage is a simple and low-cost strategy to enable long term preservation and environmentally friendly utilization of agricultural by-products, such as straws and distiller's grains (DG) for ruminants. Effect of mixing different proportions of DG and rice straw (i.e. 0, 10, 20 or 30% of DG) with or without 5% molasses addition on fermentation and chemical variables of silages was evaluated. The study was conducted as a randomized blocks design in a 4 × 2 factorial arrangement, with three replications, using laboratory silos of 1L capacity (n=24). Despite a significant interaction (P<0.01) between DG and molasses addition was observed for most variables, in general the increased addition of DG linearly decreased the pH value, acetic acid (AA), butyric acid (BA) and ammonia N concentration (P<0.01), and increased the lactic acid (LA) concentration (P<0.01). Exception was the propionic acid concentration which linearly decreased without molasses addition and linearly increased with molasses addition at increased proportion of DG (P<0.01). In both silages with or without molasses the addition of DG increased the dry matter, water soluble carbohydrates and crude protein (P<0.01), and decreased the NDF content (P<0.01). Based on the perspective of maximum utilization of rice straw, the mixture of 10% of DG associated to 5% molasses at ensilage process is recommended.

RESUMO: Ensilagem é uma estratégia simples e de baixo custo que habilita a preservação de sub-produtos agrícolas por longo tempo e com mínimo impacto ambiental, tal como a preservação de palha de arroz e resíduos da destilação de grãos (DG) para uso na alimentação de ruminantes. O objetivo deste estudo foi avaliar o efeito de incluir diferentes proporções de DG e palha de arroz (i.e. 0, 10, 20 or 30% of DG) com ou sem inclusão de 5% de melaço sobre variáveis da fermentação e composição química do material ensilado. O estudo foi conduzido em blocos casualizados em um esquema fatorial 4 × 2, com três repetições, utilizando mini-silos de 1L de capacidade (n=24). Embora a interação entre DG e melaço foi significativa (P<0,01) para a maior parte das variáveis, em geral a adição de DG diminuiu linearmente o pH e as concentrações de ácido acético, ácido butírico e amônia (P<0,01), e aumentou linearmente a concentração de ácido láctico (P<0,01). Exceção foi a concentração de ácido propiônico que diminuiu linearmente sem a adição de melaço enquanto aumentou linearmente com a adição de melaço, à incrementados níveis de inclusão de DG (P<0,01). Em ambos casos, com ou sem adição de melaço, a adição de DG aumentou linearmente o teor de matéria seca, de carboidratos solúveis em água e de proteína bruta, e diminuiu o teor de fibra em detergente neutro do material ensilado the NDF content (P<0,01). Baseado na perspectiva de máxima utilização de palha da arroz, recomenda-se a mistura de 10% de DG associado com 5% de melaço no processo de ensilagem.

RESUMO

Ensilage is a simple and low-cost strategy to enable long term preservation and environmentally friendly utilization of agricultural by-products, such as straws and distiller's grains (DG) for ruminants. Effect of mixing different proportions of DG and rice straw (i.e. 0, 10, 20 or 30% of DG) with or without 5% molasses addition on fermentation and chemical variables of silages was evaluated. The study was conducted as a randomized blocks design in a 4 × 2 factorial arrangement, with three replications, using laboratory silos of 1L capacity (n=24). Despite a significant interaction (P<0.01) between DG and molasses addition was observed for most variables, in general the increased addition of DG linearly decreased the pH value, acetic acid (AA), butyric acid (BA) and ammonia N concentration (P<0.01), and increased the lactic acid (LA) concentration (P<0.01). Exception was the propionic acid concentration which linearly decreased without molasses addition and linearly increased with molasses addition at increased proportion of DG (P<0.01). In both silages with or without molasses the addition of DG increased the dry matter, water soluble carbohydrates and crude protein (P<0.01), and decreased the NDF content (P<0.01). Based on the perspective of maximum utilization of rice straw, the mixture of 10% of DG associated to 5% molasses at ensilage process is recommended.(AU)

Ensilagem é uma estratégia simples e de baixo custo que habilita a preservação de sub-produtos agrícolas por longo tempo e com mínimo impacto ambiental, tal como a preservação de palha de arroz e resíduos da destilação de grãos (DG) para uso na alimentação de ruminantes. O objetivo deste estudo foi avaliar o efeito de incluir diferentes proporções de DG e palha de arroz (i.e. 0, 10, 20 or 30% of DG) com ou sem inclusão de 5% de melaço sobre variáveis da fermentação e composição química do material ensilado. O estudo foi conduzido em blocos casualizados em um esquema fatorial 4 × 2, com três repetições, utilizando mini-silos de 1L de capacidade (n=24). Embora a interação entre DG e melaço foi significativa (P<0,01) para a maior parte das variáveis, em geral a adição de DG diminuiu linearmente o pH e as concentrações de ácido acético, ácido butírico e amônia (P<0,01), e aumentou linearmente a concentração de ácido láctico (P<0,01). Exceção foi a concentração de ácido propiônico que diminuiu linearmente sem a adição de melaço enquanto aumentou linearmente com a adição de melaço, à incrementados níveis de inclusão de DG (P<0,01). Em ambos casos, com ou sem adição de melaço, a adição de DG aumentou linearmente o teor de matéria seca, de carboidratos solúveis em água e de proteína bruta, e diminuiu o teor de fibra em detergente neutro do material ensilado the NDF content (P<0,01). Baseado na perspectiva de máxima utilização de palha da arroz, recomenda-se a mistura de 10% de DG associado com 5% de melaço no processo de ensilagem.(AU)

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RESUMO

A rice straw - cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 °C, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L(-1).

RESUMO

A rice straw -cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 ºC, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L-1.(AU)

Assuntos

RESUMO

A rice straw -cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 ºC, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L-¹.

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RESUMO

The aims were to explore an appropriate isolating medium for obtaining purple nonsulfur bacteria (PNSB) for use as biofertilizers in saline paddy fields and to obtain pure cultures. We therefore chose a defined isolating medium containing 0.25 percent NaCl, (Glutamate-Acetate broth, GA) and a rice straw broth to compare them for numbers of PNSB obtained, time to obtain pure cultures, diversity and costs. A total of 30 water and 30 sediment samples were collected from saline paddy fields in southern Thailand and used to isolate PNSB in both the isolating media. Based on 60 samples and a period of 13 days incubation under anaerobic light conditions, a greater number of samples produced PNSB growth in GA broth after only day 3; however, after that the rice straw broth provided about a 2 fold increase in the number of samples that produced PNSB growth. Colonies isolated from GA broth required a significantly higher number of repeated streaking to obtain a pure culture (average 3.5) than those from rice straw broth (average 2.7) and the latter medium also produced significantly (P < 0.05) more isolates per sample. Sixty samples of water and sediment, from rice paddies with salinity (average, 3.43 +/- 0.67 mS/cm) and slight acidity (average, pH 5.84 +/- 0.42) provided 62 PNSB isolates by GA broth and 210 isolates by rice straw broth, and rice straw broth also produced a greater prevalence of PNSB. Estimates of the costs based on current prices of media, Gas Pak and electricity to obtain PNSB with the use of GA broth was roughly 6 times higher than for the rice straw broth.

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Physiological studies were conducted to determine the optimum cultural conditions for maximal carboxymethyl cellulase (CMCase) formation by Aspergillus terreus DSM 826. Shaking condition at 150 rpm is favorable for the production of CMCase from rice straw and sugar cane bagasse. The highest enzyme yield was obtained at the third day of incubation at 30ºC for both cases; however CMCase formation occurred at a broad range of pH values, with maximal formation of A. terreus DSM 826 CMCase at pH 4.5 and 5.0 when rice straw and sugar cane bagasse were used as sole carbon source, respectively. Carboxymethyl cellulose (CMC) was found to be a good inducer for CMCase formation in both agricultural wastes with CMC concentrations of 0.5 and 1.0 % (w/v) in case of rice straw and sugar cane bagasse, respectively. High level of enzyme formation was obtained with the addition of ammonium chloride as nitrogen source in both cases and at a concentration of 0.4 % (v/v Tween-80) as an addition to medium containing rice straw. However this addition did not influence the production of CMCase in case of using sugar cane bagasse as carbon source.

Assuntos

RESUMO

Physiological studies were conducted to determine the optimum cultural conditions for maximal carboxymethyl cellulase (CMCase) formation by Aspergillus terreus DSM 826. Shaking condition at 150 rpm is favorable for the production of CMCase from rice straw and sugar cane bagasse. The highest enzyme yield was obtained at the third day of incubation at 30 °C for both cases; however CMCase formation occurred at a broad range of pH values, with maximal formation of A. terreus DSM 826 CMCase at pH 4.5 and 5.0 when rice straw and sugar cane bagasse were used as sole carbon source, respectively. Carboxymethyl cellulose (CMC) was found to be a good inducer for CMCase formation in both agricultural wastes with CMC concentrations of 0.5 and 1.0 % (w/v) in case of rice straw and sugar cane bagasse, respectively. High level of enzyme formation was obtained with the addition of ammonium chloride as nitrogen source in both cases and at a concentration of 0.4 % (v/v Tween-80) as an addition to medium containing rice straw. However this addition did not influence the production of CMCase in case of using sugar cane bagasse as carbon source.

RESUMO

Physiological studies were conducted to determine the optimum cultural conditions for maximal carboxymethyl cellulase (CMCase) formation by Aspergillus terreus DSM 826. Shaking condition at 150 rpm is favorable for the production of CMCase from rice straw and sugar cane bagasse. The highest enzyme yield was obtained at the third day of incubation at 30ºC for both cases; however CMCase formation occurred at a broad range of pH values, with maximal formation of A. terreus DSM 826 CMCase at pH 4.5 and 5.0 when rice straw and sugar cane bagasse were used as sole carbon source, respectively. Carboxymethyl cellulose (CMC) was found to be a good inducer for CMCase formation in both agricultural wastes with CMC concentrations of 0.5 and 1.0 % (w/v) in case of rice straw and sugar cane bagasse, respectively. High level of enzyme formation was obtained with the addition of ammonium chloride as nitrogen source in both cases and at a concentration of 0.4 % (v/v Tween-80) as an addition to medium containing rice straw. However this addition did not influence the production of CMCase in case of using sugar cane bagasse as carbon source.

RESUMO

The aim of this report is to desenhe the occurrence of the physiological disease "Parrot beak" in flooded rice grown in Rio de Janeiro state soils. The symptoms occurred particularly in the presence of decomposing organic material, affecting the yield because of the high percentage of sterile spickelets.

O objetivo deste trabalho é relatar a ocorrência da doença fisiológica Bico de Papagaio em arroz irrigado cultivado em solos do Estado do Rio de Janeiro. Os sintomas manifestaram-se significativamente na presença de material orgânico em decomposição afetando o rendimento de arroz, dada a elevada percentagem de espiguetas estéreis.

RESUMO

The aim of this report is to desenhe the occurrence of the physiological disease "Parrot beak" in flooded rice grown in Rio de Janeiro state soils. The symptoms occurred particularly in the presence of decomposing organic material, affecting the yield because of the high percentage of sterile spickelets.

O objetivo deste trabalho é relatar a ocorrência da doença fisiológica Bico de Papagaio em arroz irrigado cultivado em solos do Estado do Rio de Janeiro. Os sintomas manifestaram-se significativamente na presença de material orgânico em decomposição afetando o rendimento de arroz, dada a elevada percentagem de espiguetas estéreis.

RESUMO

The aim of this report is to desenhe the occurrence of the physiological disease "Parrot beak" in flooded rice grown in Rio de Janeiro state soils. The symptoms occurred particularly in the presence of decomposing organic material, affecting the yield because of the high percentage of sterile spickelets.

O objetivo deste trabalho é relatar a ocorrência da doença fisiológica Bico de Papagaio em arroz irrigado cultivado em solos do Estado do Rio de Janeiro. Os sintomas manifestaram-se significativamente na presença de material orgânico em decomposição afetando o rendimento de arroz, dada a elevada percentagem de espiguetas estéreis.