Selection and optimization of extracellular lipase production using agro-industrial waste

The aim of this study was to isolate and select lipase-producing microorganisms originated from different substrates, as well as to optimize the production of microbial lipase by submerged fermentation under different nutrient conditions. Of the 40 microorganisms isolated, 39 showed a halo around the colonies and 4 were selected (Burkholderia, Bacillus sp., Penicillium lanosum and Corynebac glutamyl), where strains showing lipolytic halo Radius (R) / colony radius (r) ratio greater than 2.0 were selected. The results of submerged fermentation expressed as enzymatic activity revealed that the genera of microorganisms significantly influenced the enzymatic reaction, and lipase obtained from Burkholderia cepacia was the most promising, with activity of 0.0058 U.mL-1. It was also observed in the optimization step of lipase production that the sodium nitrate content (NaNO3) had a positive effect on enzyme production, and its increase was indicative of higher enzymatic activity. The addition of sources of organic nitrogen (corn steep liquor, p = 0.2398), carbon (soybean oil, p = 0.3379), magnesium MgSO4.7H2O (p = 0.4189) and potassium KH2PO4 (p = 0.8562) had no significant effects on the lipase production and could result in decreased production of extracellular lipases.Keywords: Burkholderia cepacia, hydrolytic enzymes, residue, submerged fermentationAfrican Journal of Biotechnology, Vol. 13(4), pp. 566-573, 22 January, 201

Viabilidade econômica da implantação de um sistema de coleta e secagem

O objetivo deste trabalho foi estudar a viabilidade econômica da implantação de um sistema de coleta e secagem da polpa residual de lavagem de batatas na linha de processamento de batatas fritas, para ser utilizada em snacks fritos, visando o aproveitamento de resíduos agroindustriais, como novo ingrediente para a indústria de alimentos. O método payback foi estudado, este é um método de avaliação direto, no qual calcula-se o número de anos que decorrerão até que os fluxos de caixa acumulados igualem ao montante do investimento inicial. De acordo com os resultados obtidos, a empresa irá economizar 19,8 % de farinha de trigo mensalmente, com a substituição da farinha de trigo por polpa residual de lavagem da batata desidratada (PRLBD), no processamento de snacks fritos. O payback para a compra e implantação do sistema de secagem da PRLBD será pago em aproximadamente 16 meses. Este estudo demonstrou que o projeto é viável do ponto de vista econômico, além de contribuir na diminuição do impacto ambiental e com sustentabilidade da empresa, proporcionando um destino adequado para os resíduos agroindustriais

Etude d'un procédé de dépollution basé sur le couplage ozone/charbon actif pour l'élimination des phtalates en phase aqueuse

In order to comply with the standards governing the discharge of industrial effluents (Water Framework Directive, target date 2021) concerning micropollutants, in particular phthalates, innovative wastewater treatment processes have to be used. The present research addresses this issue through a study of ozone/activated carbon coupling. After determining the textural and chemical properties of several activated carbons, the efficiency of this coupling for the removal of phthalates was tested according to the following criteria: degradation kinetics of the target pollutants and evolution of both toxicity and mineralization during the process. Compared to the classical methods (ozonation or adsorption used separately), coupling proved to be highly efficient. It enables the fast removal of pollutants with a significant decrease in mineralization and toxicity. Coupling also proved to be efficient for the treatment of more complex matrices such as municipal wastewater treatment outflow. Moreover, the activated carbon properties which favour the process have also been determined. It is shown that, in this coupling, the material acts as a radical initiator and promoter (the reactions are mainly radical in nature) and as a reaction support. Lastly, the study also shows that in situ regeneration of the activated carbon, which would be economically attractive, could be achieved during the process.Le respect des normes de rejets aqueux industriels imposées par la directive cadre sur l’eau (échéances en 2021) concernant les micropolluants, et notamment les phtalates, nécessite la mise au point de procédés de traitement innovants. L’étude du procédé basé sur le couplage ozone/charbon actif a ainsi été effectuée. Après la détermination des propriétés chimiques et texturales des charbons actifs testés, l’efficacité de ce couplage pour l’élimination des phtalates a été éprouvée selon plusieurs critères : cinétique d’élimination des polluants cibles, évolution de la minéralisation et de la toxicité au cours du traitement. La comparaison des résultats obtenus avec ceux de méthodes classiques (ozonation et adsorption seules) a mis en évidence le fort potentiel du couplage ozone/charbon actif, qui permet d’obtenir une élimination rapide des polluants ainsi qu’une minéralisation et une détoxification avancées dans toutes les conditions expérimentales testées. Ce couplage c’est aussi révélé efficace lors du traitement de matrices plus complexes, telle qu’une eau de sortie de station d’épuration. En outre, cette étude a permis de déterminer les propriétés chimiques et texturales du charbon actif favorisant ce procédé. Il a aussi été montré que ce matériau joue un rôle d’initiateur et de promoteur de radicaux libres (les réactions sont très majoritairement de nature radicalaire) ainsi que de support réactionnel. Enfin, cette étude a montré qu’une régénération in situ du matériau, économiquement très intéressante, pourrait être obtenue au cours du traitement

Study of ozone/activated carbon process for the removal of phthalates in aqueous phase

Le respect des normes de rejets aqueux industriels imposées par la directive cadre sur l’eau (échéances en 2021) concernant les micropolluants, et notamment les phtalates, nécessite la mise au point de procédés de traitement innovants. L’étude du procédé basé sur le couplage ozone/charbon actif a ainsi été effectuée. Après la détermination des propriétés chimiques et texturales des charbons actifs testés, l’efficacité de ce couplage pour l’élimination des phtalates a été éprouvée selon plusieurs critères : cinétique d’élimination des polluants cibles, évolution de la minéralisation et de la toxicité au cours du traitement. La comparaison des résultats obtenus avec ceux de méthodes classiques (ozonation et adsorption seules) a mis en évidence le fort potentiel du couplage ozone/charbon actif, qui permet d’obtenir une élimination rapide des polluants ainsi qu’une minéralisation et une détoxification avancées dans toutes les conditions expérimentales testées. Ce couplage c’est aussi révélé efficace lors du traitement de matrices plus complexes, telle qu’une eau de sortie de station d’épuration. En outre, cette étude a permis de déterminer les propriétés chimiques et texturales du charbon actif favorisant ce procédé. Il a aussi été montré que ce matériau joue un rôle d’initiateur et de promoteur de radicaux libres (les réactions sont très majoritairement de nature radicalaire) ainsi que de support réactionnel. Enfin, cette étude a montré qu’une régénération in situ du matériau, économiquement très intéressante, pourrait être obtenue au cours du traitement.In order to comply with the standards governing the discharge of industrial effluents (Water Framework Directive, target date 2021) concerning micropollutants, in particular phthalates, innovative wastewater treatment processes have to be used. The present research addresses this issue through a study of ozone/activated carbon coupling. After determining the textural and chemical properties of several activated carbons, the efficiency of this coupling for the removal of phthalates was tested according to the following criteria: degradation kinetics of the target pollutants and evolution of both toxicity and mineralization during the process. Compared to the classical methods (ozonation or adsorption used separately), coupling proved to be highly efficient. It enables the fast removal of pollutants with a significant decrease in mineralization and toxicity. Coupling also proved to be efficient for the treatment of more complex matrices such as municipal wastewater treatment outflow. Moreover, the activated carbon properties which favour the process have also been determined. It is shown that, in this coupling, the material acts as a radical initiator and promoter (the reactions are mainly radical in nature) and as a reaction support. Lastly, the study also shows that in situ regeneration of the activated carbon, which would be economically attractive, could be achieved during the process

Degradation kinetics of DEP in water by ozone/activated carbon process: Influence of pH

International audienceEfficiency of the ozone (O$_3$)/Activated Carbon (AC) process to remove phthalates was studied by investigating the degradation kinetics of diethylphthalate (DEP) chosen as model pollutant. The influence of pH was determined by performing experiments at five pH values (2.5 < pH < 7.2). The kinetic contribution of radical mechanisms (δ$^{HO•}$) was estimated by using a radical scavenger (tert-butyl alcohol). Single ozonation of DEP was first performed. Pseudo-first order modelling shows that the reaction depends on pH, with kinetic constants varying from 0.0036 min$^{−1}$ (pH = 2.5) to 0.6129 min$^{− }$1 (pH = 7.2). Ozonation was then performed in the presence of a commercial AC (Pica L27), whose chemical and textural properties had been previously determined. Pseudo-first-order modelling shows a significant increase in DEP degradation kinetics: kinetic constants rose from 0.290 min$^{−1}$ (pH = 2.5) to 0.866 min$^{−1}$ (pH = 7.2). Estimation of the kinetic contribution of heterogeneous reactions to DEP removal (δ$^{hetero}$) shows that in acidic conditions, reactions are essentially located on the AC surface (δ$^{hetero}$ = 98.7% at pH = 2.5) and occur in the bulk liquid when pH increases (δ$^{hetero}$ = 29.2% at pH = 7.5). Lastly, estimation of the kinetic contribution of radical mechanisms (δ$^{HO•}$) shows that the increase in the DEP degradation kinetics is mainly due to radical reactions, with δ$^{HO•}$ increasing from 87.9% (pH = 2.5) to 92.0% (pH = 7.5). These radical reactions may be promoted by deprotonated acid groups present on the AC surface

Use of ozone/activated carbon coupling to remove diethyl phthalate from water: Influence of activated carbon textural and chemical properties

International audienceThe presence of phthalates in the environment and especially in surface waters and sediments is a major environmental concern. The aim of this work was to study diethyl phthalate (DEP) removal by a water treatment process based on the coupling of ozone (O$_3$) and activated carbon (AC). The main objective was to study the influence of AC properties on the process efficiency and on the coupling mechanism (nature and location of reactions). DEP degradation kinetics by O$_3$/AC coupling was studied by using four commercial ACs whose chemical and textural properties had been previously determined (Boehm titration, N$_2$ adsorption isotherm at 77 K, $pH_{PZC}$ determination). Degradation kinetics was correctly modelled by a pseudo-first order kinetic model based on the sum of all the effects occurring during the treatment (r$^2$ > 0.987). Results show that degradation efficiency depends both on textural properties (microporous and external surfaces favour this treatment) and chemical functions (both acid and basic functions favour radical hydroxyl generation). Experiments performed with a radical scavenger show that in all the experimental conditions used, DEP is mainly degraded by radical reactions. Moreover, it is demonstrated that AC acts more as a radical initiator and promoter and a reaction support than as an adsorbent material. The influence of pH on the reaction efficiency and mechanism is also proved: in acidic conditions (pH < 5) radical reactions are due to O$_3$/AC interactions, and they are due to indirect ozonation in the bulk liquid for higher pH

Produção de lipase extraída de resíduos aquosos: cinética da atividade enzimática

Submitted by Luciana Ferreira ([email protected]) on 2018-05-02T14:08:57Z No. of bitstreams: 2 Artigo - Tatianne Ferreira de Oliveira - 2014.pdf: 950700 bytes, checksum: 04188d807a87689bc9e8459ef54a7982 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira ([email protected]) on 2018-05-02T14:52:25Z (GMT) No. of bitstreams: 2 Artigo - Tatianne Ferreira de Oliveira - 2014.pdf: 950700 bytes, checksum: 04188d807a87689bc9e8459ef54a7982 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2018-05-02T14:52:25Z (GMT). No. of bitstreams: 2 Artigo - Tatianne Ferreira de Oliveira - 2014.pdf: 950700 bytes, checksum: 04188d807a87689bc9e8459ef54a7982 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-12Lipases are an important group of enzymes with various applications in the food, chemical and pharmaceutical industry, besides having great interest for the treatment of effluents with high lipid content. The objective of this study was to isolate, characterize and select lipolytic bacteria that produce lipase from aqueous waste effluents and to study the enzymatic activity kinetics of the extract obtained via submerged fermentation. The results obtained are promising, being possible to isolate and characterize 23 lipase-producing microorganisms, mostly gram-positive bacteria, but after the fermentation step in a liquid medium, gram negative bacteria showed the highest enzymatic activity (56.72 U.L -1 for STP 2A` bacterium and 81.99 U.L -1 for R2B). In the enzymatic activity kinetic study with the selected bacterium (R2B), among the six variables (temperature, pH, minimal mineral medium, soybean oil, glucose and sodium nitrate), temperature was the one that most positively influenced the enzymatic activity, and the best results were obtained at 40°C. It was concluded that the enzyme extract obtained from environmental waste may be used to treat the effluent and contribute to reduce environmental impacts.As lipases são um importante grupo de enzimas com diversas aplicações na indústria alimentar, química e farmacêutica, além de ter grande interesse para o tratamento de efluentes com alto teor de lipídios. Objetivou-se, neste trabalho, isolar, caracterizar e selecionar bactérias lipolíticas produtoras de lipase, a partir de efluentes residuais aquosos, assim como estudar a cinética da atividade enzimática do extrato obtido via fermentação submersa. Os resultados obtidos foram promissores, sendo possível isolar e caracterizar 23 microrganismos potencialmente produtores de lipase, sendo a maioria das bactérias Gram Positivas, porém após a etapa de fermentação em meio líquido, os Gram Negativos apresentaram as maiores atividades enzimáticas (56,72 U.L -1 para a bactéria ETE 2A` e 81,99 U.L -1 para a R2B). No estudo cinético da atividade enzimática com a bactéria selecionada (R2B), das seis variáveis (temperatura, pH, meio mínimo mineral, óleo de soja, glicose, e nitrato de sódio), a temperatura foi a que mais influenciou na atividade enzimática, tendo efeito positivo, e os melhores resultados foram obtidos a 40 °C. Concluiu-se que o extrato enzimático obtido, a partir de resíduos ambientais, poderão ser utilizados no próprio tratamento do efluente e contribuir na redução dos impactos ambientais