Potential of Klebsiella oxytoca for 1,3-propanediol production from glycerol under excess substrate conditions

Glycerol, a by-product of biodiesel, is a source of carbon for the bioproduction of chemical intermediates with high commercial value, such as 1,3-propanediol. One strain of Klebsiella oxytoca, isolated from soil samples, was tested to determine its potential to produce 1,3-propanediol through fermentation of a glycerol solution, under excess substrate conditions. The microbial growth curve was evaluated by optical density reading using a spectrophotometer (600 nm), while glycerol consumption and concentration of the products were determined by high performance liquid chromatography (HPLC) with HPX 87H column (BioRad). Formate, 3-hydroxypropionaldehyde and ethanol were produced in the early hours of fermentation. The increased rate of glycerol consumption and the formation of 1,3-propanediol coincides with formate degradation. This indicates that formate degradation likely works as an alternative means to generate part of the nicotine adenine dinucleotide (NADH) used by the 1,3-propanediol-dehydrogenase enzyme. Yield in mole of product per 100 mol of substrate reached 48.5, which is higher than that of previously investigated K. oxytoca strains.Keywords: Klebsiella oxytoca, glycerol, fermentation, 1,3-propanediol, biodiese

Influência da adição fracionada de vinhaça na produção de biogás

The objective of the present work was to quantify and determine the composition of biogas produced by anaerobic biodigestion of stillage in natura and concentraded by Moringa oleifera, using different volumes of industrial slush from a gelatin factory as a source of microorganisms. The experiment was carried out in batch reactors with approximate volume of 125 mL, and controlled temperature (30  ºC) and agitation for a period of 120 hours. Vinasse concentrated and in natura were used, and the treatments had different amounts of vinasse addition every 24 hours. The volume of produced biogas and concentration of gas components (CH4, N2, H2S and CO2) were determined. The objective of the work was to determine the ideal fractionation volume of vinasse for add on the sludge, when inoculating material for biodigestion. The best result was obtained with the most fractionated additions of vinasse, however, should be performed further studies on the use of Moringa oleifera associated with the waste being digested.O presente trabalho teve como objetivo quantificar e determinar a composição do biogás produzido por meio da biodigestão anaeróbia de vinhaça in natura e concentrada por Moringa oleifera, utilizando-se, como fonte de microrganismos, diferentes volumes de um lodo industrial proveniente de indústria de gelatina. O experimento foi conduzido em reatores de bancada com volume de, aproximadamente, 125 mL, com temperatura (30  ºC) e agitação controladas por um período de 120 horas. Foram utilizadas vinhaça na forma in natura e na forma concentrada, onde os tratamentos apresentavam diferentes volumes de adição de vinhaça a cada 24 horas. Foram determinados o volume de biogás produzido e a concentração dos componentes gasosos CH4, N2, H2S e CO2. O trabalho teve como objetivo determinar um volume ideal de fracionamento da vinhaça para adição ao lodo, na inoculação de material para biodigestão.  O melhor resultado foi obtido com as adições mais fracionadas de vinhaça, no entanto, devem-se realizar mais estudos para o uso de Moringa oleifera associado a resíduos a serem digeridos

Assessment of the delivery of citronella oil from microcapsules supported on wool fabrics

Essential oils are complex, volatile liquid mixtures that can be extracted from various parts of plants. Their main characteristics are strong fragrance and biological properties. Studying the characteristics of oils along with the possibility of an interaction with textiles creates new possible uses of this material. However, when oil is applied to a textile substrate, it is necessary to develop an oil release model, while most of the works only explore the application procedure and the fixed oil durability against washes. Thus, this work reports the mechanism and kinetics of controlled release of microencapsulated citronella oil from wool. The microencapsulation was done by complex coacervation with gelatin and gum Arabic biopolymers as shell materials. Optical microscopy, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to confirm the encapsulation. The microcapsules were then supported by foulard in wool, fixed on fabrics and evaluated by attenuated total reflection Fourier-transform infrared spectroscopy. The controlled release of citronella from the microcapsules deposited on the fabric was studied in vitro. The microcapsules formed had a multi-core structure, and when applied to wool they showed diffusion by a Fickian mechanism in the first release stage and on the second stage changed to non-Fickian kinetics. The controlled release indicates that the textile structure influences the release model due to an interaction between fabric and waterPostprint (author's final draft

Laccases in food processing: Current status, bottlenecks and perspectives

Background: Laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) catalyze the oxidation of a wide variety of organic and inorganic substrates, typically p-diphenols with a concomitant reduction of oxygen (O2) to water. Several molecules naturally occurring in foods and beverages (e.g., phenols, carbohydrates, unsatured fatty acids and thiol-containing proteins) can be modified by laccases. Hence, the interaction between laccase and these molecules can and has been widely explored by the food industry for various technological purposes. Scope and approach: The present work aims at providing a critical review on the current uses of laccases in food processing, at discussing the main bottlenecks for its popularization, and at presenting future perspectives. Both scientific reports and patents, covering preferably the last five years, were considered. Key findings and conclusions: Several traditional uses of laccases in food processing including baking, beverage, and dairy industries were detailed. Special efforts were developed, however, in analyzing future perspectives. The latter includes the application of laccases in the synthesis of new compounds with functional properties, such as antioxidant and antimicrobial activities. No less attention was devoted to the recent developments in the field of crosslinking of polymers, such as proteins and polysaccharides. Scaling up of the production of the laccase itself and especially of the novel products derived from its applications in the food sector will be essential for cost reduction and, consequently, for market expansion.This work was supported by the National Council of Scientific and Technological Development (CNPq, Proc. 404898/2016-5). R.C.G. Corrêa is a research grant recipient of Cesumar Institute of Science Technology and Innovation (ICETI). C.G. Kato (Proc. 151189/2019-6), E. Backes (Proc. 304406/2019-8), R.M. Peralta, R.A. Peralta, R.F. Peralta Muniz Moreira and A. Bracht are research grant recipients from CNPq.info:eu-repo/semantics/publishedVersio

<b>Influence of culture medium pH on the production of CGTase by <em>Bacillus firmus</em> Strain No. 37</b> - doi: 10.4025/actascitechnol.v35i3.15882

<p class="aresumo">The enzyme cyclomaltodextrin-glucanotransferase (CGTase) is a transglicosidase able to convert corn starch into cyclodextrin (CD). CDs are widely applied in industry given the ability to form inclusion complexes with a great variety of organic molecules. Regarding the optimum pH of CGTase, values reported in the literature vary according to the enzyme producing microorganism, being 8.0 the optimum pH of CGTase produced by <em>Bacillus firmus</em> Strain No. 37. This work studied the influence of the pH of culture medium with different concentration of nutrients on the production of the enzyme CGTase by <em>Bacillus firmus</em> Strain No. 37. For this purpose, the microorganism was grown in three culture media with different concentrations of carbon and nitrogen. The pH control was performed by adding sodium carbonate. The fermentation process was analyzed by the following methods: Bradford (1976) method to determine soluble proteins, DNS method to analyze sugars, and the method of complexation with β-CD to analyze the enzyme activity. The best result for CGTase enzyme activity was 0.22 U mL^-1, obtained with medium containing 2.0% soluble corn starch and yeast extract, and pH 8.3.</p> <p class="apalavrachave"> </p

<b>Controle ótimo em reator batelada alimentada para a hidrólise enzimática da celobiose</b> - DOI: 10.4025/actascitechnol.v25i1.2236

A glicose pode ser obtida através da hidrólise enzimática pelas enzimas do complexo celulase. a hidrólise da celobiose pela celobiase exibe inibição pelo substrato e pelo produto, que reduzem a performance da reação. os trabalhos sobre esta hidrólise enzimática disponíveis na literatura foram conduzidos em reatores batelada, portanto um estudo sobre a possibilidade de utilização de outro tipo de reator ainda não foi realizado para esta hidrólise. o objetivo deste trabalho é analisar o uso de um reator batelada alimentada para esta reação enzimática. a política de alimentação foi determinada utilizando a teoria de controle ótimo, onde a conversão do substrato e a concentração do produto final foram maximizadas. os resultados simulados foram comparados com dados experimentais obtidos por calsavara <em>et al</em>. (1999) em um reator batelada e indicaram que a inibição pelo substrato se sobrepõe a inibição pelo produto. a operação em batelada alimentada mostrou-se vantajosa em algumas situações

Kinetics of the simultaneous production of b- and g-cyclodextrins catalyzed by CGTase from alkalophilic Bacillus sp. - doi: 10.4025/actascitechnol.v35i4.13944

The cyclodextrins (CDs) are cyclic maltooligosaccharides obtained by cyclization of linear chains of starch, catalyzed by the enzyme cyclomaltodextringlucanotransferase (CGTase). The interest in CD production results from the formation of inclusion complexes, which allow many important applications, especially in food, pharmaceutical and cosmetic industries. The substances complexed generally have their properties modified by complexation. It is appreciated if increased solubility and higher thermal and chemical stabilities are obtained. In this work, a kinetic model was developed for the production of cyclodextrins in the presence of CGTase from alkalophilic Bacillus sp., taking into account the reversibility of the cyclization reaction, the simultaneous production of b and g-CD and also the inhibitory influence of the substrate and products (CDs), on the enzymatic activity of the CGTase. The substrate formed from a solution of maltodextrins was treated as a single substrate. The model was compared with experimental results of 24h of reaction and this comparison demonstrated that there was a very good representation of the data throughout the test period. The model also allowed explaining the observation of different experimental values for each Michaelis-Menten constant and substrate inhibition constant for each CD, although the CDs are produced from the same substrate.

Agricultural recycling of biodigested vinasse for lettuce production

The agricultural use of waste products represents an interesting alternative for nutrient cycling. Biodigested vinasse, the final waste product of vinasse biodigestion and biogas production, can be reused for agricultural purposes. The present work sought to quantify the shoot dry mass production of lettuce plants, as well as foliar nitrogen, phosphorus and potassium content following the application of biodigested vinasse on soil. Biodigested vinasse was produced from anaerobic vinasse digestion, using anaerobic sludge as a source of microorganisms. The treatments, with four replications in entirely randomized design, consisted of anaerobic sludge from a gelatin factory, vinasse in natura, biodigested vinasse and a control treatment. The experiment was conducted over 45 days using 5 L vases and applying a dose equivalent to 150 m³ ha-1. Lettuce treated with biodigested vinasse showed higher shoot dry mass production and higher accumulation of nitrogen, phosphorus and potassium in its leaves than that treated with vinasse in natura

Influência do tamanho das partículas na solubilização enzimática da proteína do farelo de soja = The influence of particle size in the enzymatic extraction of soybean meal protein

O objetivo deste trabalho foi verificar a influência do tamanho das partículas na quantidade de proteína solubilizada a partir do farelo de soja. O farelo foi peneirado e cada fração foi submetida à hidrólise enzimática com as proteases Alcalase e Flavourzyme. Ashidrólises foram realizadas a 60ºC, agitação de 100 rpm, concentração de Alcalase 0,5% (proteína/proteína) por 3h e concentração de Flavourzyme 1% (proteína/proteína) por 5h. A quantidade de proteína solubilizada foi determinada pelo método de Lowry. A análisegranulométrica do farelo mostrou que quase metade da amostra corresponde a partículas maiores que 1,68 mm. O modelo que resultou em melhor ajuste dos dados foi o GGS, e o diâmetro médio de Sauter da amostra foi 1,150 mm. Com relação à hidrólise enzimática,para as duas enzimas foi verificada uma tendência de aumento na quantidade solubilizada para as frações mais finas e maior efetividade da Alcalase na solubilização proteica. The objective of this work was to verify the influence of particlesize in the results of enzymatic extraction of soybean meal protein. The meal was classified in homogeneous fractions, and each was subjected to enzymatic hydrolysis with Alcalase and Flavourzyme proteases. The hydrolyses were conducted at 60ºC, with agitation of 100 rpm, 0.5% concentration of Alcalase (protein/protein) for three hours, and 1% concentration of Flavourzyme (protein/protein) for five hours. The results were analyzed based on the amount of solubilized protein, determined through the Lowry method. The granulometric analysis of the meal showed that almost half of the sample is composed of particles larger that 1.68 mm. The model that resulted in the best adjustment of experimental data was GGS, and the Sauter mean diameter of the sample was 1.150 mm. Regarding enzymatic hydrolysis, a trend of increase in the amount of solubilized proteinwas verified for both enzymes for the finer fractions and greater effectiveness of Alcalase in the protein extraction