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Making Plastics from Garbage
Author(s) -
Sakai Kenji,
Taniguchi Masayuki,
Miura Shigenobu,
Ohara Hitomi,
Matsumoto Toru,
Shirai Yoshihito
Publication year - 2003
Publication title -
journal of industrial ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.377
H-Index - 102
eISSN - 1530-9290
pISSN - 1088-1980
DOI - 10.1162/108819803323059406
Subject(s) - lactic acid , food waste , fermentation , chemistry , polymerization , waste management , yield (engineering) , lactide , organic chemistry , pulp and paper industry , food science , materials science , bacteria , polymer , biology , composite material , genetics , engineering
Summary We propose a novel recycling system for municipal food waste that combines fermentation and chemical processes to produce high‐quality poly‐L‐lactate (PLLA) biodegradable plastics. The process consists of removal of endogenous D, L‐lactic acid from minced food waste by a propionibacterium, L‐lactic acid fermentation under semisolid conditions, L‐lactic acid purification via butyl esterification, and L‐lactic acid polymerization via LL‐lactide. The total design of the process enables a high yield of PLLA with high optical activity (i.e., a high proportion of optical isomers) and novel recycling of all materials produced at each step, with energy savings and minimal emissions. Approximately 50% of the total carbon was removed, mostly as L‐lactic acid, and 100 kg of collected food waste yielded 7.0 kg PLLA (about 34% of the total carbon). The physical properties of the PLLA yielded in this manner were comparable to those of PLLA generated from commercially available. L‐lactic acid. Evaluation of the process is also discussed from the viewpoints of material and energy balances and environmental impact.