NoodleCycle BioConversion: Transforming Expired Instant Noodles into a Plant-Supporting Soil Resource Through Microbial Processing
Seeun Jang
US International School, Seoul, Republic of Korea
Publication date: July 10, 2026
US International School, Seoul, Republic of Korea
Publication date: July 10, 2026
DOI: http://doi.org/10.34614/JIYRC2026I16
ABSTRACT
Food waste is a major environmental challenge because it wastes embedded nutrients, water, energy, and labor while contributing to greenhouse gas emissions when disposed of through landfill or incineration. This problem is especially difficult for highly processed food waste, which is often poorly suited for conventional biological recycling. Expired instant noodles represent one such waste stream because of their high starch, oil, salt, and seasoning content, which may inhibit plant growth if applied directly to soil. This study investigated whether expired instant noodles could be converted into a plant-supporting soil resource through microbial pretreatment using Bacillus subtilis. In a prototype-scale experiment, crushed expired noodles and seasoning were biologically processed and then incorporated into soil at low and high doses. Bok choy (Brassica rapa subsp. chinensis) was used as the test plant, and germination and early seedling growth were evaluated across four groups: untreated control soil, unprocessed noodle-amended soil, fermented low-dose soil, and fermented high-dose soil. The unprocessed noodle group showed a strong inhibitory effect, with germination reduced to 45% compared with 92% in the control. In contrast, the fermented low-dose group restored germination to 90%, while the fermented high-dose group reached 78%. During days 7–14, the unprocessed group remained stunted, whereas the fermented low-dose group showed substantially improved root and shoot growth. These findings suggest that microbial pretreatment can reduce the phytotoxicity of oily and salty processed food waste and support its conversion into a more plant-compatible soil input.
Food waste is a major environmental challenge because it wastes embedded nutrients, water, energy, and labor while contributing to greenhouse gas emissions when disposed of through landfill or incineration. This problem is especially difficult for highly processed food waste, which is often poorly suited for conventional biological recycling. Expired instant noodles represent one such waste stream because of their high starch, oil, salt, and seasoning content, which may inhibit plant growth if applied directly to soil. This study investigated whether expired instant noodles could be converted into a plant-supporting soil resource through microbial pretreatment using Bacillus subtilis. In a prototype-scale experiment, crushed expired noodles and seasoning were biologically processed and then incorporated into soil at low and high doses. Bok choy (Brassica rapa subsp. chinensis) was used as the test plant, and germination and early seedling growth were evaluated across four groups: untreated control soil, unprocessed noodle-amended soil, fermented low-dose soil, and fermented high-dose soil. The unprocessed noodle group showed a strong inhibitory effect, with germination reduced to 45% compared with 92% in the control. In contrast, the fermented low-dose group restored germination to 90%, while the fermented high-dose group reached 78%. During days 7–14, the unprocessed group remained stunted, whereas the fermented low-dose group showed substantially improved root and shoot growth. These findings suggest that microbial pretreatment can reduce the phytotoxicity of oily and salty processed food waste and support its conversion into a more plant-compatible soil input.
