History of silk and in part replaced natural silk. Following the crisis in Europe, the modernization of sericulture in Japan made it the world's foremost silk producer. By the early 20th century, rapidly industrializing Japan was producing as much as 60 percent of the world's raw silk, most exports shipping through the port of Yokohama. Italy managed to rebound from the crisis, but France was unable. Urbanization in Europe saw many French and Italian agricultural workers leave silk growing for more lucrative factory work. Raw silk was imported from Japan to fill the void. Asian countries, formerly exporters of raw materials (cocoons and
Silk means used to achieve degradation of silk in vitro. Protease XIV from Streptomyces griseus and α-chymotrypsin from bovine pancreases are the two popular enzymes for silk degradation. In addition, gamma-radiation, as well as cell metabolism, can also regulate the degradation of silk. Compared with synthetic biomaterials such as polyglycolides and polylactides, silk is obviously advantageous in some aspects in biodegradation. The acidic degraded products of polyglycolides and polylactides will decrease the pH of the ambient environment and thus adversely influence the metabolism of cells, which is not an issue for silk. In addition, silk materials can retain strength over a