Degradation of Proteins and Starch by Combined Immobilization of Protease, α-Amylase and ß-Galactosidase on a Single Electrospun Nanofibrous Membrane.

Two commercially available enzymes, Dextrozyme (α-amylase) and Esperase (protease), were covalently immobilized on non-woven electrospun poly(styrene-co-maleic anhydride) nanofiber mats with partial retention of their catalytic activity. Immobilization was achieved for the enzymes on their own as well as in different combinations with an additional enzyme, ß-galactosidase, on the same non-woven nanofiber mat. This experiment yielded a universal method for immobilizing different combinations of enzymes with nanofibrous mats containing maleic anhydride (MAnh) residues in the polymer backbone.

Estrogenic activity, chemical levels and health risk assessment of municipal distribution point water from Pretoria and Cape Town, South Africa.

Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and have been detected in drinking water from various countries. Although various water treatment processes can remove EDCs, chemicals can also migrate from pipes that transport water and contaminate drinking water. This study investigated the estrogenic activity in drinking water from various distribution points in Pretoria (City of Tshwane) (n = 40) and Cape Town (n = 40), South Africa, using the recombinant yeast estrogen screen (YES) and the T47D-KBluc reporter gene assay. The samples were collected seasonally over four sampling periods. The samples were also analysed for bisphenol A (BPA), nonylphenol (NP), di(2-ethylhexyl) adipate (DEHA), dibutyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP), diisononylphthalate (DINP), 17ß-estradiol (E2), estrone (E1) and ethynylestradiol (EE2) using ultra-performance liquid chromatography-tandem mass spectrophotometry (UPLC-MS/MS). This was followed by a scenario based health risk assessment to assess the carcinogenic and toxic human health risks associated with the consumption of distribution point water. None of the water extracts from the distribution points were above the detection limit in the YES bioassay, but the EEq values ranged from 0.002 to 0.114 ng/L using the T47D-KBluc bioassay. BPA, DEHA, DBP, DEHP, DINP E1, E2, and EE2 were detected in distribution point water samples. NP was below the detection limit for all the samples. The estrogenic activity and levels of target chemicals were comparable to the levels found in other countries. Overall the health risk assessment revealed acceptable health and carcinogenic risks associated with the consumption of distribution point water.

Lipoxygenases: From Isolation to Application.

The positive effect of lipoxygenase, added as an enzyme-active soy flour, during the production of white bread is well established. In addition to increasing the mixing tolerance and overall dough rheology, lipoxygenase is also an effective bleaching agent. It is known that these effects are mediated by enzyme-coupled cooxidation of gluten proteins and carotenoids. However, the mechanism whereby these effects are achieved is not yet fully understood. In order to gain a better understanding into the reactions governing the beneficial effects of lipoxygenases in bread dough, an in-depth knowledge of the lipoxygenase catalytic mechanism is required. Until now no single review combining the molecular enzymology of lipoxygenase enzymes and their application in the baking industry has been presented. This review, therefore, focuses on the extraction and molecular characterization of lipoxygenases in addition to the work done on the application of lipoxygenases in the baking industry.