Development of Microbial Enzyme which separates Cadmium from Marine Wastes

扇贝肝胰脏和鱿鱼肝是扇贝和鱿鱼加工过程中产生的废弃物，其倾倒已成为北海道的一个严重问题。这些组织含有大量的镉，这是一种有毒的重金属。微生物去除镉从肝胰腺匀浆，进行了研究，利用这种废物的增值蛋白质资源。用各种市售蛋白酶消化（溶解）肝胰腺组织。在一种蛋白酶处理中溶解器官的产率为83%。用酶消化的肝胰腺匀浆培养黄单胞菌UR No.2，镉的去除率达96.0%。通过富集培养，以扇贝肝胰脏和鱿鱼肝为碳源和氮源，对能在培养基中生长的微生物进行了筛选。从土壤和活性污泥中富集培养产生了八种不同的细菌。通过模型试验，测定了分离的土壤细菌培养上清液的蛋白酶活性。一株土壤分离物具有较高的胞外蛋白酶活性，可提高扇贝肝胰腺和鱿鱼肝组织蛋白质的溶解性，从蛋白质资源增值的角度考虑，需要对扇贝加工废弃物精巢（性腺）进行溶解。以扇贝精巢为碳源和氮源，通过富集培养，筛选出能在培养基中生长的微生物。一个土壤分离物，具有高的胞外蛋白酶活性，导致在扇贝精巢组织的溶解增强。

Dumping of scallop hepatopancreas and squid liver, a waste of scallop and squid processing, has become a serious problem in Hokkaido. These tissues contain a large amount of cadmium, which is a toxic heavy metal. Microbial removal of cadmium from a homogenate of hepatopancreas, was examined to use this waste for value-added protein resources. Hepatopancreas tissues were digested (solubilized) by the various market proteases. Yield of solubilization of the organ in one protease treatment was 83%. During cultivation of the strain Xanthomonas sp. UR No.2 in the homogenate of hepatopancreas digested by the proteases, 96.0% of cadmium was removed. That is, these enzyme and organism are effective for the removal of cadmium from the protease treated homogenate of hepatopancreas.Microorganisms were screened on the basis of the ability to grown in the medium with scallop hepatopancreas or squid liver as a carbon and nitrogen sources by enrichment culture. Enrichment culture from soil and activated sludge yielded eight different bacteria. Soil bacteria isolated were assayed by protease activity of culture supernatant with model experiment. One soil isolate has high extracellular protease activity, resulting in an enhancement of solubilization of protein of scallop hepatopancreas and squid liver tissues.Solubilization of testis (gonad), a waste of scallop processing, is required from the viewpoint of the preparation of value-added protein resources. Microorganisms were screened on the basis of the ability to grow in the medium with scallop testis as a carbon and nitrogen sources by enrichment culture. One soil isolate, has high extracellular protease activity, resulting in an enhancement of solubilization of scallop testis tissues.