No abstract

We examined the enzymatic synthesis of astaxanthin n-octanoic acid esters. Carriers for the immobilized enzyme and reaction conditions such as water content, reaction temperature, and time were examined using Candida cylindracea lipase (Lipase OF ® ). Lipase OF ® immobilized by a hydrophobic anion exchange resin (10% w/w content of lipase) gave the best yield in the esterification reaction of astaxanthin. Two milligrams of astaxanthin per 750 mL tri-n-octanoin (ca. 0.3%) was optimum because of the low solubility of tri-n-octanoin. The esters were obtained in a yield of 36.4% under the optimal reaction conditions.

Two types of lipids rich in arachidonic acid content were encapsulated using various saccharides as the wall material, and the oxidation processes of the encapsulated lipids were measured at /*ῌ and +,ῌ relative humidity. One of the lipids contained arachidonoyl residue at a content of ca. .*ῌ, and another was a structured lipid, the major component of which was +,--octanoyl-,-arachidonoyl glycerol. Microencapsulation e#ectively retarded their oxidation. In particular, among the tested saccharides, soluble soybean polysaccharide and gum arabic were the best two wall materials for the suppression of both lipids.

Carbon and nitrogen sources were investigated for improving peroxidase production by Arthromyces ramosus, a hyperproducer of peroxidase. Glucose as carbon source and a mixture of yeast extract and polypeptone at the ratio of 3 to 5 as nitrogen source in a production medium were shown to give the highest peroxidase activity. During the culture amino acids such as alanine, arginine, methionine, leucine, tyrosine and tryptophan were depleted. Therefore, glucose supplemented nitrogen source fed-batch culture was carried out and a peroxidase activity of 73 U/ml was obtained. This activity was 1.7 times higher than that of glucose fed-batch culture. This indicates that an adequate nitrogen source supply during the culture is effective for improving the peroxidase production by A.ramosus.

No abstract