Bioleaching of Sorghum Straw in Bioreactors for Biomass Cleaning

Pretreatments are often needed for lignocellulosic biomass feedstocks before either thermochemical or biochemical conversion processes. Our previous research has demonstrated the potential of bioleaching, with its superior capability of removing certain inorganic compounds compared to water leaching, to improve biomass quality for thermochemical conversion in biofuel production. In this study, the bioleaching process was scaled up from 250 mL beakers to be carried out in custom-designed 2.5 L bioreactors. The fungus Aspergillus niger was used in the bioreactors for leaching sorghum straw biomass with an initial ash content of 6.0%. The effects of three operating parameters on leaching efficiency (i.e., residual ash content) were extensively studied, including the fungal mass added to each reactor, leaching time, and glucose concentration in the starting liquid phase. Response surface methodology (RSM) was used for the experiment design. The results showed that the average residual ash content of the sorghum feedstock after bioleaching was significantly lower (3.63 ± 0.19%) than that of the ash content (4.72 ± 0.13%) after water leaching (p < 0.00001). Among the three parameters, glucose concentration in the starting liquid phase had the most significant effect on leaching effectiveness (p = 0.0079). Based on this outcome, subsequent bioleaching experiments yielded reductions in residual ash content to as low as 2.73%.

Evaluation of the capacity of laccase secretion of four novel isolated white-rot fungal strains in submerged fermentation with lignocellulosic biomass

The capacity of novel isolated white-rot fungi secreting laccase was evaluated for various kinds of lignocellulosic biomass in submerged fermentation. The laccase secreted by Neofomitella fumosipora Han 386 and Pleurotus pulmonarius Han 527 was significantly faster than that by Coriolopsis trogii Han 751 and Coriolopsis sanguinaria An 282. Maximum laccase from N. fumosipora Han 386 on the four kinds of lignocellulosic biomass tested appeared on the first day. This phenomenon indicated that N. fumosipora Han 386 secreted laccase rapidly compared with other tested strains in this study and showed the superiority in the rate of secreting laccase. Based on the maximum laccase activity, the ability of secreting laccase of C. sanguinaria An 282 was superior to other tested novel isolated strains. On the whole, N. fumosipora Han 386 and P. pulmonarius Han 527 preferred Toona sinensis to produce laccase, C. trogii Han 751 preferred to produce laccase on Populus beijingensis, and C. sanguinaria An 282 grown on Sorghum straw was more suitable for secreting laccase. The results will be helpful for developing bioprocesses using various kinds of lignocellulosic biomass for lignocellulolytic enzyme production and enlarging the number of laccase producing strains for industrial application.

PRODUÇÃO E MANUTENÇÃO DE PALHADA DE SORGO POR APLICAÇÃO HORMÉTICA DE HERBICIDAS

PRODUÇÃO E MANUTENÇÃO DE PALHADA DE SORGO POR APLICAÇÃO HORMÉTICA DE HERBICIDAS TIAGO PEREIRA DA SILVA CORREIA1, ARTHUR GABRIEL CALDAS LOPES2, FRANCISCO FAGGION3, LEANDRO AUGUSTO FELIX TAVARES4, PAULO ROBERTO ARBEX SILVA5 1Docente da Faculdade de Agronomia e Medicina veterinária, Universidade de Brasília, Campos universitário Darcy Ribeiro ICC, cep:70910-900, Asa norte, Brasília, DF, Brasil. [email protected] 2Doutorando do PPGA da Universidade de Brasília, Campos universitário Darcy Ribeiro ICC, cep:70910-900, Asa norte, Brasília, DF, Brasil. [email protected] 3Docente da Faculdade de Agronomia e Medicina veterinária, Universidade de Brasília, Campos universitário Darcy Ribeiro ICC, cep:70910-900, Asa norte, Brasília, DF, Brasil. [email protected] 4Docente do Instituto de Ciências Agrárias da Universidade Federal dos Vales do Jequitinhonha e Mucuri, Av. Universitária, 1000, Bairro universitário, cep:38610-000, Unaí, MG, Brasil. [email protected] 5Docente da Faculdade de Ciências Agronômicas da Universidade Estadual Paulista “Júlio de Mesquita Filho”, Campos de Botucatu, Av. Universitária, 3780, cep:18610-034, Altos do paraíso, Botucatu, SP, Brasil. [email protected] RESUMO: No sistema plantio direto a manutenção de palhada sobre o solo é essencial, especialmente em regiões onde a decomposição é rápida. O objetivo do trabalho foi avaliar a aplicação de subdoses de herbicida Glifosato, 2,4 D e Haloxifope-P-Ester Metílico na produção e manutenção de palhada de sorgo ao sistema plantio direto. O experimento foi realizado na Fazenda Experimental Água Limpa, pertencente a Universidade de Brasília. Foi utilizado um esquema fatorial 3 (Herbicidas: Glifosato; 2,4-D Sal Dimetilamina; Haloxifope-P-Ester metílico) x 2 (Subdoses: 4 e 6 g i.a ha-1 de Glifosato; 0,6 e 1,2 g i.a ha-1 de Haloxifope-P-metílico; 80 e 160 g i.a ha-1 de 2,4-D Sal Dimetilamina), com quatro repetições inteiramente casualizadas. Aos tratamentos incluiu-se um testemunha sem aplicação de subdoses. As subdoses menor, maior e testemunhas foram identificadas por D1, D2 e D0 respectivamente. Os tratamentos foram aplicados 35 dias após a semeadura com pulverizador tratorizado, e a partir dos 100 dias foram avaliados teor de lignina (TL), massa de materia seca (MMS) e produtiviade de grãos. D2 de Glifosato aumenta 5,35% a MMS e 3% o TL da palhada de sorgo e não difere a produtividade de grãos da cultura. D1 de Haloxifope-P-Ester Metílico aumenta 9,2% a MMS da planta de sorgo. As subdoses dos demais herbicidas estudados reduzem a produtividade de grãos de sorgo. Palavras-chave: plantio direto, cobertura vegetal, subdose, glifosato, 2,4D. PRODUCTION AND MAINTENANCE OF SORGHUM STRAW BY HORMETIC APPLICATION OF HERBICIDES ABSTRACT: In the no-tillage system, maintaining straw over the soil is essential, especially in regions where decomposition is rapid. The work aimed to evaluate the application of underdoses of herbicide Glyphosate, 2,4 D and Haloxifope-P-Ester Methyl in the production and maintenance of sorghum straw to the no-tillage system. The experiment was conducted at the Experimental Água Limpa Farm, belonging to the University of Brasília. A factorial scheme 3 (Herbicides: Glyphosate; 2,4-D Dimethylamine salt; Haloxifop-P-methyl ester) x 2 (Subdoses: 4 and 6 g ia ha-1 of Glyphosate; 0.6 and 1.2 g Haloxifop-P-methyl ia ha-1; 80 and 160 g ia 2,4-D salt Dimethylamine), with four completely randomized repetitions. The treatments included a control without the application of underdoses. The minor, major and control subdoses were identified by D1, D2 and D0 respectively. The treatments were applied 35 days after sowing with tractor spray, and after 100 days, lignin content (TL), dry matter mass (MMS) and grain yield were evaluated. The D2 treatment of Glyphosate presents MMS 5.35% higher at 190 days after sowing. The same treatment increased the TL by 3% and did not differ in the productivity of sorghum grains. Keywords: no-till, vegetation cover, underdosing, glyphosate, 2,4D.

Comparative study of different organic mulches for increased wheat productivity district Faisalabad, Punjab, Pakistan

Weeds are major threat to global wheat production and cause serious threat to food security. Likewise, water scarcity is also a major threat to food production and its intensity is continuously soaring up across the globe. Organic mulches have potential to reduce weeds growth and conserve the soil moisture thus ensures the better crop growth and yield. Therefore, present study was conducted to compare the performance of different organic mulches in improving wheat growth and productivity. The study was comprised of different organic mulches; M1= No mulch (control) M2= maize straw mulch, M3= wheat straw mulch, M4= sorghum straw mulch and M5= rice straw mulch and three nitrogen levels N1 = 90 kg, N2 = 120 kg and N3= 150 kg/ha. The results indicated that both organic mulches and N rates had significant impact on growth, and yield traits. The maximum leaf area index (LAI), crop growth rate (CGR), productive tillers (307 m-2), grains/spike (46.22), 1000 grain weight (42.33 g) biological yield (13.76 t/ha) and grain yield 4.75 t/ha was obtained with sorghum straw mulch and minimum productive tillers (255.33 m-2), grains/spike (36.22), biological yield (11.46 t/ha) and grain yield (3.59 t/ha) was recorded in no mulch (control). Among nitrogen levels maximum productive tillers (290.6 m-2), grains/spike (42.80), 1000 grain weight (40.65 g), biological yield (13.44 t/ha) and grain yield (4.32 t/ha) was obtained with 150 kg/ha N and minimum productive tillers (274 m-2), grains/spike (38.13), 1000 grain weight (36.94 g) biological yield (11.98 t/ha) and grain yield (3.90 t/ha) was obtained with 90 N kg/ha. Thus, farmers can use sorghum straw mulch and N (150 kg ha-1) to improve the wheat productivity. However, farmers must be educated by government institute and adoptive research farms in order to understand and adaption of this approach.

Compression characteristics and the influencing factors of sweet sorghum straw: Experimental study

The rheological properties of the compression process of sweet sorghum straw were studied. The selected experimental factors comprised of the compression density, cutting length, compression speed, and moisture content, and specific energy consumption were selected as the evaluation index of the compression characteristics. The Box-Behnken test scheme was used to analyze the response surface test. The results showed that the selected compression model and specific energy consumption model of the sweet sorghum straw compression process were obtained. The primary factors contributing to energy consumption were the cutting length, moisture content, and compression density. The optimal parameters were as follows: a compression density of 500 kg/m3, a cutting length of 20 mm to 30 mm, a moisture content of 60.06%, and a specific energy consumption of 66 kJ/kg. The results provided methods for reducing the total energy consumption of the compression process and a theoretical basis for the compression and bundling of sweet sorghum.

Produtividade do feijão-caupi cultivado após plantas de cobertura com e sem aplicação de herbicida sem pós-emergência

The objective of this research was to evaluate the yield of the cowpea crop, when grown on cover crops straws, managed or not with herbicides applied in post-emergence. The experiment was conducted in the field, in a complete randomized block design with three replications. In a 5x2 factorial scheme, the first factor were featuredby five types of straw were tested: sorghum, congograss, Tanzania grass, palisadegrassand weeds. The second factor was characterized by the absence and application of the ready mix of bentazone + imazamox at the dose 600 + 28 g ha-1at 13 days after emergence (DAE) and the herbicide haloxifop-p-methyl at the dose of 62.35 g ha-1to 18 DAE. Weed density and dry matterwere evaluated at 20 and 85 DAE of the crop, plant height, stem diameter, chlorophyll content, dry matteraerial part and in the flowering of the crop (46 DAE). At harvest, the number of grains per pod, the number of grains per plant, the weight one hundred grains, the population of cowpea plants and grain yieldwereevaluated. The straws of congo grass, Tanzania grass and palisadegrasson the soil surface reduce the dry mass of weeds, constituting necessary management where chemical control has not been carried out. Regardless of the use of straw, the application of the herbicide is essential to guarantee the productivity of the crop. The cultivation of cowpea on sorghum straw, congograss, Tanzania grass and palisadegrassresults in higher grain yield.