Immobilization of Yeast on Polymeric Supports

Biocatalysts (enzymes and whole cells) play a crucial role in industrial processes allowing for efficient production of many important compounds, but their use has been limited because of the considerably unstable nature of enzymes. Immobilization often protects enzymes from environmental stresses such as pH, temperature, salts, solvents, inhibitors and poisons. Immobilization of cells containing specific enzymes has further advantages such as elimination of long and expensive procedures for enzymes separation and purification and it is vital to expand their application by enabling easy separation and purification of products from reaction mixtures and efficient recovery of catalyst. This review focuses on organic polymers (natural and synthetic) used as matrices for immobilization of microorganisms, mainly baker’s yeasts and potential application of immobilized cells in the chemical, pharmaceutical, biomedical and food industries

Study on the Properties of Immobilized Biocatalysts with Lipase Activity Produced by Yarrowia lipolytica in Batch Culture

Three kinds of matrices (calcium alginate, gelatin, and PVA) were employed as supports to immobilize lipases from Y. lipolytica KKP 379 via physical adsorption. The stability of biocatalysts (free and immobilized) was evaluated by measuring the enzyme activity before and after treatment with the method based on the hydrolysis of p-nitrophenyl laurate. Two fractions of enzymes were immobilized: cell-bound (yeast biomass) and extracellular (supernatant). The yield of immobilization and catalytic properties of immobilized lipases were investigated. Satisfactory results for lipolytic activity and biocatalyst stability were obtained for cell-bound enzymes immobilized in alginate (0.38 U g–1 d.m.) and crosslinked gelatin (0.18 U g–1 d.m.). Immobilization of the supernatant was successful only on the alginate (0.026 U g–1 d.m.). After lyophilization, no significant difference was noticed between treated and untreated biocatalysts. Lyophilized catalysts were successfully immobilized in all three matrices, but the process reduced their lipolytic activity probably due to an insufficient amount of water in the reaction solution. This work is licensed under a Creative Commons Attribution 4.0 International License

Aceite de germen de trigo obtenido mediante extracción con dióxido de carbono supercrítico con etanol: Composición en ácidos grasos

In this work, supercritical fluid extraction (SFE) using CO2 with ethanol as entrainer was performed at a temperature of 40 oC under a pressure of 21 MPa. For comparison, a similar extraction without the entrainer was carried out. The extraction yield of wheat germ using supercritical CO2 with ethanol was slightly higher (10.7 wt%) than that of extraction without the entrainer (9.9 wt%). Fractions of SFE extracts were collected separately during the experiments and the composition of fatty acids in each fraction was analyzed. The SFE extracted oils were rich (63.4-71.3%) in the most valuable polyunsaturated fatty acids (PUFA) and their content in all collected fractions was approximately constant. Similar PUFA contents were found in the reference samples of oils extracted by n-hexane (66.2-67.0%), while the commercial cold-pressed oil contained significantly less PUFA (60.2%). These results show a higher nutritional value of the oil obtained by extraction with supercritical CO2 than cold pressed oil which is generally considered to be very valuable.En este trabajo, la extracción con fluidos supercríticos (SFE) usando CO2 con etanol como agente de arrastre se realizó a 40 °C bajo una presión de 21 MPa. Se ha llevado a cabo la comparación con una extracción similar sin agente de arrastre. El rendimiento de la extracción de germen de trigo usando CO2 supercrítico con etanol fue ligeramente mayor (10,7% en peso) que la de extracción sin agente de arrastre (9,9% en peso). Se recogieron por separado fracciones de extractos SFE durante los experimentos y se analizó la composición de ácidos grasos en cada fracción. Los aceites extraídos mediante SFE eran ricos en los ácidos grasos poliinsaturados más valiosos (63,4-71,3%), (PUFA) y su contenido en todas las fracciones recogidas fue aproximadamente constante. Un contenido similar de PUFA fueron encontrados en muestras de referencia de los aceites extraídos con n-hexano (66,2-67,0%), mientras que el aceite prensado en frío comercial contenía significativamente menos PUFA (60,2%). Estos resultados muestran un mayor valor nutritivo del aceite obtenido por extracción con CO2 supercrítico que el aceite prensado en frío que generalmente se considera que es muy valioso

Polyphenols: A concise overview on the chemistry, occurrence, and human health

This review gives an updated picture of each class of phenolic compounds and their properties. The most common classification implies the subdivision of phenolics in two main groups: flavonoids (e.g., anthocyanins, flavanols, flavanones, flavonols, flavonones, and isoflavones) and non-flavonoids (e.g., phenolic acids, xanthones, stilbens, lignans, and tannins) polyphenols. The great interest in polyphenols is associated with their high potential application for food preservation and for therapeutic beneficial use. The relationship between polyphenol intake and human health has been exploited with special reference to cardiovascular diseases, hypertension, diabetes, metabolic syndrome, obesity, and cancer. The use of current existing databases of bioactive compounds including polyphenols is described as key tools for human health research.info:eu-repo/semantics/publishedVersio

Green chemistry in food industry

Zielona chemia dotyczy nowego podejścia do zagadnienia syntezy, przeróbki i wykorzystania związków chemicznych, co ma na celu zmniejszenie zagrożenia dla środowiska i zdrowia człowieka. W przemyśle spożywczym zielona chemia koncentruje się głównie na zastosowaniu alternatywnych dróg syntezy związków chemicznych (np. syntezy biochemiczne) oraz zastosowaniu takich warunków reakcji, które zwiększają selektywność i zmniejszają ilość odpadów oraz emisji zanieczyszczeń (np. użycie rozpuszczalników nadkrytycznych, które wykazują mniej szkodliwy wpływ na środowisko i zdrowie człowieka). W artykule przedstawiono najważniejsze procesy chemiczne i technologiczne wykorzystywane w przemyśle spożywczym, które są prowadzone zgodnie z zasadami zielonej chemii.Green chemistry concerns a new approach towards synthesis, processing and utilization of chemical compounds, which aims at reducing environment and health hazard. In food industry, green chemistry focuses mainly on alternative synthesis pathways of chemical compounds (for example biochemical synthesis) as well as on applying such reaction conditions which can on one hand increase selectivity and on the other reduce the waste quantity and atmospheric emission (for example by employing supercritical solvents, which show less harmful effect on environment and human health). This article describes the most important chemical and technological processes in food industry, which are carried out according to green chemistry rules

Biotransformations with genetically modified baker's yeast Saccharomyces cerevisiae

Baker’s yeast Saccharomyces cerevisiae is quite commonly applied as a wholecell biocatalysts in biotransformations – reactions based on enzymatic transformations of chemical compounds. Yeast cells are easy in cultivation and use. They are usually used to catalyze such reactions as bioreduction or hydrolysis. The full sequencing of its genome accompanied with achievements of genetic engineering allowed to design new yeast strains characterized by high conversion yield and reaction selectivity. Genetically modified cells of Saccharomyces cerevisiae catalyze biotransformations, which lead to chiral building blocks important in pharmaceutical industry (especially those obtained by reduction of á- and â -oxoesters). „Designer yeast” is a new catalyst for Baeyer–Villiger oxidation. Recombinant yeast lipases have been discussed as useful means in biodiesel production because the microbiological method of producing of this kind of fuel has many advantages. There is a growing interest in application of modified yeast in biotransformation reactions. Modern directions to improve catalytic abilities of baker’s yeast include: the use of surface display technology of enzymes, optimization or increase in availability of cofactor required for bioreduction reactions or gene knock-out, which eliminates the activity of enzymes with conflicting and unwanted stereoselectivities. Commonly used technique is also overexpression of the desired protein or expression of heterologous enzymes in yeast cells

The attempt to apply Yarrowia Lipolytica KKP379 yeast in fishery industry wastes management

Celem pracy przedstawionej w artykule była ocena możliwości zastosowania kilku produktów odpadowych pochodzących z przetwórni ryb (solanki, dwóch rodzajów odpadów po procesie wędzenia ryb oraz szlamu) jako źródła węgla do wzrostu dzikiego szczepu drożdży Y. lipolytica KKP 379. Najwyższy średni plon biomasy drożdży uzyskano w podłożu zawierającym szlam jako źródło węgla, natomiast najwyższą średnią aktywność lipolityczną oznaczono w płynie pohodowlanym z podłoża zawierającego olej odpadowy po procesie wędzenia. Wprawdzie średnia zewnątrzkomórkowa aktywność lipolityczna drożdży była niższa w porównaniu z uzyskaną w podłożu z oliwą z oliwek (znanym aktywatorem syntezy lipaz), ale zaletą przedstawionego rozwiązania mogą być względy ekonomiczne i ekologiczne.The aim of the study presented in the paper was to evaluate the possibility of application some fishery wastes (oily wastes from fish smoking process, fish leach and sludge) as a carbon sources in the culture medium for wild strain of yeast Y. lipolytica KKP 379. The highest average yeast biomass yield was achieved in the presence of sludge, but the highest lipase activity was observed in the presence of oily wastes from fish smoking process. The extracellular lipase activity in the culture medium was lower than that obtained in the presence of oil olive (the common activator of lipase synthesis), however this approach may be recommended due to the economic and environmental reasons