Cold active enzyme production and its utilization on angiotensin converting enzyme inhibitory bioactive peptide

The cold-active enzyme production of yeast isolates obtained from environmental samples and their utilization to obtain bioactive peptide has been investigated in the Ph.D. study. Among 18 isolates, sixteen isolates have been found to be able to produce hydrolytic enzymes at low temperatures. It has also been observed that some isolates have more than one enzymatic activity simultaneously. As a result of molecular identification analysis, isolates with enzymatic activity were found to belong to Yamadazyma spp., Rhodosporidiobolus colostri, and Cystofilobasidium capitatum species. The pectinase, amylase and protease activities of cold isolates were 0.76-1.73; 0,5-1,57 and 2,11-10,53 U / ml. In the second part of the Ph.D. study, various food industry wastes were added to the medium to be used for protease production. Among the wastes examined, the highest protease activity was measured on the medium containing mandarin peel. Optimization studies have been performed to increase protease activity after determination of the suitable food waste to be used in enzyme production. Experimental designs using Plackett Burman and Response Surfaces Methodology have shown that the protease activity of Yamadazyma spp. B514-1 isolate was increased by 2.33 fold. The protease enzyme obtained under optimum fermentation conditions was partially purified by precipitation with ammonium sulfate. In the final stage of the Ph.D. study, the cold-active protease enzyme from Yamadazyma spp. B514-1 was used in the production of the bioactive peptide. Spirulina platensis protein concentration was hydrolyzed with Yamadazyma B514-1 protease and the angiotensin-converting enzyme (ACE) inhibitory activities of the hydrolyzates were evaluated by spectrophotometric method. As a result of the studies, hydrolysates were found to have ACE inhibitory activity. ACE inhibitory peptides were also found to exhibit antifungal activity at the same time.