生物資源由来のボトル、環境負荷軽減への小さな一歩 気ままなリライト172
While the global impact on carbon emissions may be minimal, coordinated efforts at international levels have been underway to shift from fossil fuel-based PET (polyethylene terephthalate) bottles to biomass-based alternatives. Under the leadership of Suntory Holdings in Japan, four major domestic companies and two international oil-related corporations have joined together to develop large-scale bio-based PET production using waste cooking oil. This initiative is a step toward reducing reliance on fossil fuels, though the limited availability of waste cooking oil is able to only satisfy a small portion of the demand for plastic bottles. Even if fully utilized, this resource would cover only a fraction of the world’s PET bottle production, resulting in only a slight reduction in petroleum-based plastics.
Suntory’s ambitious initiative seeks to develop a PET bottle composed of 70% bio-based materials and 30% petroleum-based materials—a challenging goal that requires strong collaboration with six major domestic and international companies. Key partners include Mitsubishi Corporation, ENEOS Holdings, Neste (a Finnish company), Mitsui Chemicals, Iwatani Corporation, and Indorama Ventures PCL (a Thai company). Suntory first partnered with Mitsubishi, ENEOS, and Neste in 2023, later expanding the collaboration in October 2024 to include Mitsui Chemicals, Iwatani Corporation, and Indorama Ventures.
Suntory’s plan for bio-based PET production involves a coordinated process to mass-produce bio-based terephthalic acid (bio-TPA) from bio-paraxylene (bio-PX). The process begins with Mitsui Chemicals, which converts biomass sources into bio-based intermediates that serve as feedstock for bio-PX. Indorama Ventures PCL then handles the catalytic reforming and oxidation processes: through catalytic reforming, bio-PX is produced from these intermediates, and through oxidation, bio-TPA is created from bio-PX. This setup enables Suntory to produce enough bio-based resin to supply 45 million PET bottles, covering about 0.5% of its annual PET bottle use in the domestic beverage market. Iwatani Corporation manages the logistics, distributing the bio-based resin across Suntory’s partner network.
While Suntory’s 70% bio-based PET bottles may appear to be a promising alternative to fully fossil-based plastics, their environmental impact remains largely unchanged and may serve more as a branding strategy than a meaningful environmental breakthrough. Shifting to bio-based materials may reduce its carbon footprint during production. In terms of waste, like conventional PET, bio-based PET doesn’t biodegrade under natural conditions and will persist in the environment for hundreds of years if it ends up as litter or breaks down into microplastics. Even a 100% bio-based PET bottle has the same end-of-life environmental footprint when discarded. The chemical structure of bio-based PET is nearly identical to that of petroleum-based PET, meaning it behaves the same way in terms of durability and resistance to natural decomposition.
Although bio-PET mass production has a limited impact on the broader issues of plastic pollution in oceans and landfills, companies exploring bio-based alternatives are increasingly drawn to its appeal. Under pressure from investors and stakeholders to enhance sustainability performance and reduce carbon footprints, companies are turning to bio-PET as a way to demonstrate environmental responsibility in their sustainability reports, meet corporate social responsibility (CSR) objectives, and attract ESG-focused investment. Amid rising public concern over plastic waste and fossil fuel dependency, bio-PET is serving as a visible gesture of progress, providing companies with a cushion against public criticism and building goodwill—even though bio-PET bottles currently cost 1.5 to 3 times more than traditional fossil-based bottles. By appealing to eco-conscious consumers willing to pay a premium for products marketed as “sustainable” or “green,” companies are aiming to boost brand value and gain a competitive edge. This strategy risks creating a misleading impression of the environmental benefits of bio-PET as its actual ecological contribution is far more modest than bio-PET’s “green” image suggests.