This article, written by Japan Bioplastics Research Institute Co., Ltd. in August 2025, explains the basic knowledge of bioplastics and their application at the Osaka-Kansai Expo.
Basic Structure of Bioplastics
Bioplastics were developed to solve two challenges faced by conventional plastics and are collectively termed "plant-derived plastics" and "biodegradable plastics." For the carbon dioxide emission problem during petroleum-based plastic manufacturing, using plant-derived raw materials that absorb CO2 circulating near the earth's surface suppresses new CO2 generation. For marine plastic waste issues, biodegradable plastics that can be ultimately decomposed into water and carbon dioxide by microorganisms under certain conditions serve as countermeasures.
Characteristics and Manufacturing Process of Polylactic Acid
Polylactic acid (PLA), a representative bioplastic, uses plant-derived sugars and starches from corn, cassava, and sugarcane as raw materials, possessing both plant-derived and biodegradable characteristics. In the manufacturing process, starch is enzymatically decomposed to obtain sugars, to which lactic acid bacteria are added for fermentation to produce lactic acid (same process as yogurt production), followed by chemical polymerization to generate polylactic acid. Through improvements, heat resistance has been enhanced, and it is now used in a wide range of applications including cups, clothing, laptop computer housings, shale gas fracking repair materials, and 3D printer filaments.
Practical Examples at the Osaka-Kansai Expo
The Expo showcases multiple innovative bioplastic applications. The Japan Pavilion displays 3D printer-manufactured stools made from Mitsubishi Chemical Corporation's biomass polycarbonate DURABIOþ with added algae as part of the "Soukaku" co-creation project, designed to be decomposed into three parts for reuse after use. Kaneka Corporation exhibits Green Planet®, produced entirely through biological processes and biodegradable in marine environments, manufactured from vegetable oils by microorganisms and achieving biodegradation in both soil and seawater.
The Osaka Prefecture Healthcare Pavilion displays a massive bioplastic pipe organ created through collaboration by small and medium enterprises in western Japan from August 19-25, with pipes using Teijin's bio-polycar Panlite® (maximum length 1,630mm, diameter 101mm, 53 pipes), keyboards using Mitsubishi Chemical's DURABIO™, and pipe mouths using PLA 3D printer products. Additionally, Expo staff inner shirts use Pieclecx Co., Ltd.'s "Electric Fiber" (antibacterial fiber utilizing PLA's piezoelectric properties), with used products being composted through the "P-FACTS" system.
The article points out the importance of material selection according to purpose, noting that 100% biodegradable materials are effective for biodegradation purposes, while 50% plant-derived blends are effective for greenhouse gas reduction purposes, concluding that balanced material selection and expanded utilization are necessary.