TECHNOLOGY FOCUS - BIOLOGY - Preparation: No preparation method is given. Preferred Components: The bacterial cells exhibit all the identifying characteristics of a strain deposited with CGMCC as Accession No. 6318 or 6319, variants of the strain deposited with CGMCC as Accession No. 6318 or 6319, where the variants have all the identifying characteristics of the CGMCC No. 6318 or 6319 strain, and mutants of the strain deposited with CGMCC as Accession No. 6318 or 6319, where the mutants have all the identifying characteristics of the CGMCC No. 6318 or 6319 strain. The bacterial cells exhibit the characteristics of cells of bacterial strain YP1 deposited with CGMCC as Accession No. 6318, or exhibit the characteristics of cells of bacterial strain YT1 deposited with CGMCC as Accession No. 6319. The bacterial cells are isolated from an insect consisting of Tenebrio molitor, Zophobas morio, and Plodia interpunctella. The bacterial cells degrade an amount of the petroleum-based plastic of 100-10000 grams of the petroleum-based plastics per gram of dry weight of the cells. The isolated microbial consortium comprises one or more bacterial cells of the bacterial strain comprising YT1 and/or YP1. The petroleum-based plastic-degrading insect is a grain beetle, preferably Tenebrio molitor, Zophobas morio, or Plodia interpunctella. Preferred Composition: The composition comprises one or more cells of at least one of a bacterial strain comprising YT1 and/or YP1, where the cells comprise at least two bacterial strains, preferably six bacterial strains. The composition further comprises one or more petroleum-based plastics, where the bacterial cell/the isolated microbial consortium is cultured with the petroleum-based plastics.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method-A further comprises growing the larvae with a source of nutrients. The method-B further comprises growing the larvae with a source of nutrients, growing the larvae with a juvenile hormone or neotenin to stimulate larval growth, harvesting the larvae, and harvesting excrement from the larvae. The composition is cultured: for a period of time sufficient to degrade the petroleum-based plastics; for a period of time of 10-90 days; and at a temperature of 15-45 degrees C. The larvae are grown with the petroleum-based plastics for a period of time sufficient to degrade an amount of the petroleum-based plastics of at least 10 fold greater than the weight of the larvae. The larvae are grown with the petroleum-based plastics for a period of time of 2-480 hours, preferably 2-24 hours. The larvae are provided at a larval density of 2-10 kg/m2, preferably 3.5-6 kg/m2. The larvae are grown with the petroleum-based plastics at: a temperature of 20-35 degrees C, preferably 25-28 degrees C; a moisture content of 60-99%, preferably 80-90%; and a light to dark ratio of 16:8 or a light to dark ratio of 14:10. The larvae convert the petroleum-based plastics to carbon dioxide. The degraded petroleum-based plastic product has a molecular weight of at least 20% lower than the molecular weight of a corresponding petroleum-based plastic that has not been degraded. Preferred Components: The source of nutrients is vegetables, leafy vegetables, fruits, tubers, roots, fresh vegetable leaves, potatoes, carrots, and/or corn. The nutrients are nitrogen, phosphorus, a vitamin, and/or water. The harvested larvae are utilized as feed. The biomass product is extracted from the harvested larvae. The excrement is utilized as fertilizer. EXAMPLE - No suitable example given.