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Enzymatic Hydrolysis of Gelatin Layers on Used Lith Film Using Thermostable Alkaline Protease for Recovery of Silver and PET Film
Author(s) -
Masui Akihiko,
Yasuda Masahiro,
Fujiwara Nobuaki,
Ishikawa Haruo
Publication year - 2004
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp030058s
Subject(s) - gelatin , alkaline protease , enzyme , hydrolysis , protease , enzymatic hydrolysis , chemistry , chromatography , nuclear chemistry , biochemistry
Abstract To develop a new efficient and potential industrial enzymatic process for the recovery of silver and poly(ethylene terephthalate) (PET) from used lith film for printing, which has not been recycled at all, enzymatic hydrolysis of gelatin layers on lith film was investigated using the thermostabilized mutant enzyme of the alkaline protease from alkaliphilic Bacillus sp. B21–2. The rate of gelatin hydrolysis of lith film in a stirred‐tank reactor increased with the temperature and enzyme concentration. The time required to complete the hydrolysis of gelatin on lith film was longer than that on X‐ray film because of the tightly cross‐linked structure of the gelatin layers of lith film. The time required to complete the hydrolysis by using the mutant enzyme was less than that using the wild‐type enzyme. The gelatin hydrolysis of lith film was well explained by a model that took into consideration a number of physical processes in addition to the chemical process.