Chitosan-citric acid edible coating to control Colletotrichum gloeosporioides and maintain quality parameters of fresh-cut guava.

This study aimed to verify the action of edible chitosan-citric acid (CHI-CA) coating to control Colletotrichum gloeosporioides and maintain quality parameters of fresh-cut guava. Chitosan was obtained from Litopenaeus vannamei shells using high temperature and short exposure times. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of CHI-CA against C. gloeosporioides were determined by macrodilutions at 28 °C/120 h in the absence/presence of CHI-CA (0-10 mg/mL). Scanning electron microscopy was used to evaluate morphological changes in the fungus. Guava slices were coated with CHI-CA (MIC) or 5 mg/mL glycerol (control). Rot incidence and physicochemical, physical, and microbiological factors were determined at 0, 3, 7, and 14 days at 24 °C and 4 °C. Chitosan presented typical structural characterization, 64% deacetylation, and a molecular weight of 1.6 × 104 g/mol. CHI-CA exhibited MIC and MFC values of 5 mg/mL and 10 mg/mL, respectively, and promoted changes in the morphology and cell surface of fungal spores. The fresh-cut guava coated with CHI-CA maintained quality parameters during storage and preserved their sensorial characteristics. Therefore, the use of CHI-CA as a coating is a promising strategy for improving postharvest quality of fresh-cut fruits.

Rock biofertilizer and earthworm compost on sugarcane performance and soil attributes in two consecutive years

The deployment of soluble fertilizers has been one of the most commonly applied agricultural practices in the bid to increase crop yield. However, the production of soluble fertilizers has a considerable economic cost and consumes a substantial amount of energy. In general, soil organic matter provides the nutrients needed for plant growth in organic agriculture. However, these nutrients are not sufficient if the best yield is to be obtained. The aim of our field experiment was to evaluate the effectiveness of phosphate and potassic sources (rocks, bio-fertilizers and soluble fertilizers) based on several sugarcane characteristics and soil attributes. Our experiment was conducted over two consecutive years, and we assessed the effect of using sugarcane filter mud cake (SFMC). In addition, we mixed the phosphate and potassic sources with earthworm compost enriched in N by inoculation with diazotrophic bacteria (OM) and applied at 50, 100 and 150 % of the recommended dosage rate (RDR). The PK biofertilizer with OM enriched in N positively affected sugarcane height, yield, and industrial characteristics. The application of SFMC greatly increased available P and K in the soil and plant characteristics with residual effect in the two consecutive harvests. We conclude that the biofertilizer has the potential to increase sugarcane characteristics and may represent an alternative to soluble fertilizers.(AU)

Rock biofertilizer and earthworm compost on sugarcane performance and soil attributes in two consecutive years

The deployment of soluble fertilizers has been one of the most commonly applied agricultural practices in the bid to increase crop yield. However, the production of soluble fertilizers has a considerable economic cost and consumes a substantial amount of energy. In general, soil organic matter provides the nutrients needed for plant growth in organic agriculture. However, these nutrients are not sufficient if the best yield is to be obtained. The aim of our field experiment was to evaluate the effectiveness of phosphate and potassic sources (rocks, bio-fertilizers and soluble fertilizers) based on several sugarcane characteristics and soil attributes. Our experiment was conducted over two consecutive years, and we assessed the effect of using sugarcane filter mud cake (SFMC). In addition, we mixed the phosphate and potassic sources with earthworm compost enriched in N by inoculation with diazotrophic bacteria (OM) and applied at 50, 100 and 150 % of the recommended dosage rate (RDR). The PK biofertilizer with OM enriched in N positively affected sugarcane height, yield, and industrial characteristics. The application of SFMC greatly increased available P and K in the soil and plant characteristics with residual effect in the two consecutive harvests. We conclude that the biofertilizer has the potential to increase sugarcane characteristics and may represent an alternative to soluble fertilizers.

Interspecies variation of Kitasatospora recifensis endophytic from yam bean producing thermostable amylases in alternative media.

An endophytic actinomycete isolated from tubers of yam beam (Pachyrhizus erosus L. Urban) was classified as a novel species nominated Kitasatospora recifensis based in phenotypic and genotypic analysis (16S rDNA gene sequence). Monosporic culture using specific ISP2 media revealed three interspecies, which were identified by DNA southern hybridization (Wild strain 13817 W, Aerial Mycelium strain 13817 AM and Vegetative Mycelium strain 13817 VM). The strains were tested for the production of amylolitic enzymes in alternative media. Maximum yields for both enzymes were observed in starch-casein. Higher α-amylase was obtained with strain 13817 W in starch-urea, and amyloglucosidase with strain 13817 AM in starch-ammonium that are economic sources and may be important for industrial purposes. Type strain (DAUFPE 13817(T) = KCTC 9972(T )= DSM 44943(T)).

Growth of Cunninghamella elegans UCP 542 and production of chitin and chitosan using yam bean medium

Microbiological processes were used for chitin and chitosan productions by Cunninghamella elegans (UCP 542) grown in a new economic culture medium. The assay was carried out to evaluate the growth of C. elegans using yam bean (Pachyrhizus erosus L. Urban) medium, in different times of growth (24, 48, 72 and 96 hrs), incubated at 28°C in an orbital shaker at 150 rpm. The lyophilized biomass was determined by gravimetry. The polysaccharides were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, titration and viscosity. C. elegans grown in the yam bean medium and produced higher yields of biomass (24.3 g/ mL) in 96 hrs. The high level was chitosan (66 mg/g), and chitin (440 mg/g) were produced at 48 and 72 hrs of growth, respectively. The polysaccharides showed degree of deacetilation and viscosimetric molecular weight as: 6.2 percent and 3.25 x10(4) g/mol for chitin, and 85 percent and 2.72 x 10(4) g/mol for chitosan, respectively. The results obtained suggest high biotechnological potential of yam bean as an economic source to produce chitin and chitosan by C. elegans. In addition, the new medium using yam bean for production of the chitin and chitosan may be used for many purposes to reduce the cost price of fermentation processes.

Efetividade do inoculante com Bradyrhizobium sp em diferentes substratos / Effectivenees of Bradyrhizobium sp inoculants on different substrates

Resumo: Objetivando determinar as condiçöes ideais para a sobrevivência e efetividade do Bradyrhizobium sp em substratos alternativos com diferentes potenciais matriciais, foi conduzido u experimento utilizando-se como veículo de inoculaçäo os substratos: diatomia, vinhaça, seca, vermiculita e composto urbano em relaçäo à turfa. A inoculaçäo foi procedida com a estirpe UMKL-58, selecionada em trabalhos anteriores. Os substratos foram submetidos aos m de -0,33, -1,0 e -3,00 bar e incubados por 240dias. Para a qualificaçäo dos veiculos foram feitos testes de sobrevivência da estirpe nos materiais utilizando-se os métodos de diluiçäo em placas e de infecçäo em plantas coma leguminosa cunhä (Clitoria ternatea L.) nos intervalos de 0, 12, 30, 60, 90, 120, 150, 180 e 240dias após a inoculaçäo, como também, avaliaçäo da eficiência da fixaçäo biológica do N2 em funçäo do veículo de inoculaçäo. Os resultados demonstram que o Bradyrhizobium sobreviveu melhor na diatomita submetida a m -3,0 bar e nos demais potenciais foi comparável a turfa. Para todos os veículos, observou-se que altos valores de m reduzirama taxa de sobrevivência da bactéria como também afetaram a qualidade do inóculo diminuindo a efetividade da estirpe (au)