Inhibitor tolerance of a recombinant flocculating industrial Saccharomyces cerevisiae strain during glucose and xylose co-fermentation

ABSTRACT Lignocellulose-derived inhibitors have negative effects on the ethanol fermentation capacity of Saccharomyces cerevisiae. In this study, the effects of eight typical inhibitors, including weak acids, furans, and phenols, on glucose and xylose co-fermentation of the recombinant xylose-fermenting flocculating industrial S. cerevisiae strain NAPX37 were evaluated by batch fermentation. Inhibition on glucose fermentation, not that on xylose fermentation, correlated with delayed cell growth. The weak acids and the phenols showed additive effects. The effect of inhibitors on glucose fermentation was as follows (from strongest to weakest): vanillin > phenol > syringaldehyde > 5-HMF > furfural > levulinic acid > acetic acid > formic acid. The effect of inhibitors on xylose fermentation was as follows (from strongest to weakest): phenol > vanillin > syringaldehyde > furfural > 5-HMF > formic acid > levulinic acid > acetic acid. The NAPX37 strain showed substantial tolerance to typical inhibitors and showed good fermentation characteristics, when a medium with inhibitor cocktail or rape straw hydrolysate was used. This research provides important clues for inhibitors tolerance of recombinant industrial xylose-fermenting S. cerevisiae.

Minimum effective release rate of antifoulants.1. Effects of zosteric acid at Ford Island, Hawaii (USA).

Minimum effective release rate (MERR) of zosteric acid (ZA) was studied at Ford Island. At laboratory condition, spore attachment in Enteromorpha intestinalis was inhibited significantly at 28.2 microg cm2 of ZA. More than 95% reduction in spore attachment was achieved in Ulva fasciata at 2,000 microM of ZA through membrane diffusion system. At 40 cm depth level larval settlement was high with maximum number of Hydroides elegans settlement. The overall larval settlement was increased with increasing days of exposure. The MERR of 10 microg cm(-2) d(-1) ZA inhibited 50% of the larval settlement. However, the inhibition rate was not proportionate to the antifouling ZA concentration. Using MERR membrane diffusion system an effective antifouling strategy was suggested for Ford Island.

Antifouling activity of six nontoxic chemicals on spore attachment of Ulva fasciata.

Marine biofouling cause severe damage to all marine technologies. Indiscriminate use of toxic metallic antifouling (AF) chemicals (cuprous oxide and TBT) to control the biofouling in turn greatly affects the flora and fauna of the marine ecosystem. In search of environmentally safe and effective AF agents, six nontoxic AF candidates were studied against the spore attachment of Ulva fasciata. Spore attachment was inhibited at 100 microg of trans-cinnamic acid (TCA) and benzoic acid (BA). Sulfate-coumaric acid (SCA) had no significant effect on the spore attachment. The release rate of BA exhibited a constant release flow. Varied response of U. fasciata spores to AF chemicals and release rate to the surrounding medium are discussed.

Estudo in vitro da influência do condicionamento ácido e da superfície, em dentina de dentes decíduos, na resistência de uniäo de resina composta e na micromorfologia dessa dentina condicionada / In vitro effect of type and time of etching of deciduous teeth dentin on tensile bond strength of composite and on dentine micromorphology

A pesquisa teve a finalidade de avaliar in vitro a resistência de uniäo, por ensaio de traçäo, empregando o sistema adesivo Scotchbond Multi-Purpose Plus e o compósito Z100, e a micromorfologia, pelo emprego do MEV, em dentina de dentes decíduos. Os fatores estudados foram: ácidos fosfórico, a 35 por cento (P35) e 10 por cento (P10), e maléico, a 10 por cento (M10), ou suas ausências; tempo de condicionamento ácido, de 5 e 15 segundos; superfícies de ensaio, vestibular e oclusal. Os resultados permitiram concluir que: sem condicionamento, a retentividade foi muito baixa; o P10 apresentou a maior retentividade com o condicionmento de 15 segundos; P35 com 5 segundos de condicionamento, apresentou baixa retentividade; em média as superfícies apresentaram retentividades semelhantes, mas que dependem do tempo e do ácido; o padräo de condicionamento ácido parece näo apresentar relaçäo confiável com a resistência de uniäo

Efeito de condicionamento ácido na morfologia do esmalte / Effect of the acid conditioning on the enamel morphology

A efetiva retençäo da resina sobre a superfície de esmalte depende diretamente do condicionamento do mesmo. A exposiçäo do esmalte dentário humano em soluçöes ácidas produz in vitro três padröes condicionadores clássicos. Este artigo se propoë a revisar a açäo dos ácidos sobre o esmalte dentário, a necessidade ou näo de profilaxia previamente à aplicaçäo ácida e o tempo condicionador necessário para que se promova uma boa interaçäo do material resinoso com a interface dentária

Prevention of human fascioliasis: a study of the role of acids detergents and potassium permanganate in clearing salads from metacercariae

Prevention of human fascioliasis could depend on clearing the leafy salads from the metacercariae. The present work evaluated the role of some chemicals in detaching and killing this infective stage. It was observed that washing in running water for 10 minutes detached only 50% of the metacercariae. Citric acid in the concentration of [10 ml/L], commercial vinegar [120 ml/L], liquid soap [12 ml/L] and KMnO4 [24 mg/L] detached all metacercariae after 10 minutes exposure. The use of vinegar and KMnO4 was recommended; the former is lethal to other parasites in the vegetables, the second destroyed the metacercariae. Vegetable leaves were not softened and remained fresh

Resistencia del esmalte a la disolución ácida y su correlación con la caries dental / Enamel resistence to acid dissolution and tooth decay

La resistencia del esmalte a la disolución ácida es un factor que influye en la susceptibilidad a la caries. Los propósitos del presente estudio fueron determinar la resistencia del esmalte a la disolución ácida a través de la técnica colorimétrica (RM) y correlacionar los datos obtenidos con la prevalencia de caries. Se seleccionaron 271 niños entre los siete y nueve años de edad, con los incisivos centrales superiores permanentes erupcionados, y se realizó el registro de los índices CPO-d y ceo-d y la prueba de resistencia del esmalte RM a través de un muestreo probabilístico de conveniencia en dos delegaciones, (seis escuelas públicas del Distrito Federal). De la muestra el 56.4 por ciento, registró esmalte muy resistente, el 27.3 por ciento menos resistente y el 16.2 por ciento poco resistente. El 57.9 por ciento se encontró libre de caries en la dentición permanente y el 10 por ciento en la dentición temporal; el promedio del índice CPO-D fue de 0.93 ñ 1.34 y del ceo-d 4.71 ñ 3.1. Los datos sugieren que la distribución de la resistencia del esmalte no es homogénea y que ésta aumenta proporcionalmente conforme al tercio de erupción (p< 0.05); el factor de correlación de Spearman fue negativo y estadísticamente significativo (p<0.05). La técnica RM demostró la existencia de individuos con diferente resistencia del esmalte a la disolución ácida

Porosimetria do esmalte condicionado por ácido / Porosimetry of etched enamel

Empregando um porosímetro de mercúrio, os autores determinaram os diâmetros dos poros produzidos na superfície do esmalte dental, após condicionamento por 3 soluçöes ácidas comerciais. Foram determinados os seus níveis de efetividade por meio da relaçäo dos poros de diâmetros médios e de maior freqüência