In this study, partially puriWed lysozyme was incorporated into zein Wlms in combination with chickpea albumin extract (CPAE), bovine serum albumin (BSA) and disodium EDTA. The zein Wlms showed an inherent free radical scavenging activity. Incorporation of lysozyme did not contribute to soluble free radical scavenging activity of zein Wlms. However, the incorporation of lysozyme in combination with CPAE increased the soluble and immobilized free radical scavenging activity of zein Wlms 17% to 25% and almost 84%, respectively. The incorporation of CPAE also improved the distribution of partially puriWed lysozyme preparation in zein Wlms and enabled the controlled release of lysozyme by reducing its release rate from zein Wlms between 1.5-and 3.5-fold, depending on the concentration of incorporated CPAE. In contrast, the BSA incorporation made distribution of lysozyme more heterogeneous and it did not contribute to the free radical scavenging activity of Wlms signiWcantly. The combinational incorporation of partially puriWed lysozyme with disodium EDTA · 2H 2 O or CPAE and disodium EDTA · 2H 2 O gave zein Wlms eVective on Escherichia coli and Bacillus subtilis. This study clearly showed the beneWts of using functional protein extracts to control lysozyme distribution and release rate and to improve antioxidant activity in zein Wlms.
An extracellular lipase producing bacterium was isolated from a soil sample, and identified as a strain of Pseudomonas fluorescens by 16S rRNA gene sequencing. It was named Pseudomonas fluorescens KE38. KE38 showed psychrotolerant properties with an optimum growth temperature of 25 °C. The lipase enzyme secreted by KE38 was purified 41.13-fold with an overall yield of 54.99%, and a specific activity of 337.3 U/mg. The molecular mass of purified lipase was estimated to be approximately 43 kDa by SDS-PAGE. Although the lipase was active at a temperature range of 15-65 °C, it exhibited maximum activity at 45 °C, at pH 8.0. The enzyme exhibited high stability retaining 100% and 70% of its activity after an incubation period of 45 and 100 min at 45 °C and pH 8.0 respectively. It also showed a broad substrate specificity acting on p-nitrophenyl esters with C8-C18 acyl groups as substrates and was activated by Ca2+ and Ni2+ at 1 mM. While the enzyme retained its activity levels in the presence of a variety of organic solvents, DMSO and dimethylformamide enhanced this. High stability, broad substrate specificity and activity at cold temperatures in the presence of organic solvents, and metal ions make the extracellular lipase of KE38 a candidate for industrial applications.State Planning Agency of Turke
A combination of culture-dependent and independent methods was used in an attempt to identify the bacteria present in kefir grains and kefir liquid. Culture-independent methods involved direct extraction of DNA by mechanical means from either grains or liquid, followed by PCR amplification and sequencing of 16S rRNA genes. Culture-dependent methods were performed by inoculating samples from both the kefir grains and the kefir liquid to solid media followed by incubation under either aerobic or anerobic conditions in order to selectively enrich aerobic and anaerobic bacteria. Pure cultures were isolated from enriched bacteria and their DNA was extracted for the amplification and sequencing of 16S rRNA genes. Results indicate that kefir grains had a different bacterial composition compared to the kefir liquid. While Lactobacillus kefiranofaciens, Lactobacillus kefiri, Enterococcus faecium and Acetobacter syzygii were found only in the kefir grains, Lactobacillus helveticus was found only in the kefir liquid. On the other hand, Lactococcus lactis subsp. lactis, Leuconostoc mesenteroides and Acetobacter lovaniensis were found to be present in both the grains and the liquid. To the best of our knowledge, this work is the first to report the presence of A.lovaniensis, A. syzygii and Enterococcus faecium in kefir.
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