Isolation and identification of a novel antioxidant with antitumour activity from Serratia ureilytica using squid pen as fermentation substrate.

The antioxidant activity of the culture supernatant of Serratia ureilytica TKU013 with squid pen as the sole carbon/nitrogen source was assessed by three methods, and the phenolic contents were assayed. The supernatant with the highest antioxidant activity was further purified by liquid-liquid partition, revealing the ethyl acetate extract exhibited the strongest antioxidant activity and the highest total phenolic content. Eight fractions were retrieved from silica gel column chromatography of this extract, designated F1-F8.

Conversion of squid pen by Serratia ureilytica for the production of enzymes and antioxidants.

Two proteases (P1 and P2) and a chitinase (C1) were purified from the culture supernatant of Serratia ureilytica TKU013 with squid pen as the sole carbon/nitrogen source. The molecular masses of P1, P2 and C1 determined by SDS-PAGE were approximately 50 kDa, 50 kDa and 60 kDa, respectively. The optimum pH, optimum temperature, pH stability, and thermal stability of P1, P2 and C1 were (pH 10, 40 degrees C, pH 7-11, and <50 degrees C), (pH 10, 40 degrees C, pH 8-11, and <40 degrees C) and (pH 6, 50 degrees C, pH 5-8, and <50 degrees C), respectively.

Purification and characterization of a chitosanase from Serratia marcescens TKU011.

A chitosanase was purified from the culture supernatant of Serratia marcescens TKU011 with shrimp shell wastes as the sole carbon/nitrogen source. Zymogram analysis revealed the presence of chitosanolytic activity corresponding to one protein, which was purified by a combination of ion-exchange and gel-filtration chromatography. The molecular weight of the chitosanase was 21 kDa and 18 kDa estimated by SDS-PAGE and gel-filtration, respectively.