Potential competing interests: No potential competing interests to declare.Although the document promises something very interesting, it seems more like a literature review.The results are minimal, and the literals 4.1.2-4.1.7 are part of the methodology but are in the results; they should be in the methodology with a greater description of how the analysis was done.In the results, tables 1 and 2 should be together to save space and make comparison easy, and, as the bioethylene results could not be achieved, they should eliminate it from the research objectives.