Wastes and undervalued coproducts from biofuel industries as raw materials for new industrial products: Greener pathway for a sustainable bioeconomy

Abstract

The biofuels like bioethanol, biobutanol and biodiesel derived from plant and forest resources are getting a great deal of attention across the world. In lingo-cellulosic biomass conversion into ethanol, the substantial quantity of low or negative value leftovers such as lignin, carbon dioxide and residues need value-added uses. In ligno-cellulosic ethanol industries; ethanol and lignin are produced at ∼1:1 on a quantum basis. Similarly in dry-milling corn ethanol production process, one bushel of corn produces 1/3rd as ethanol, 1/3rd as carbon dioxide and rest 1/3rd as Distillers' Dried Grains with Solubles (DDGS). Soy meal (SM), canola meal (CM), jatropha meal (JM) and crude glycerol are considered as coproducts and byproducts from the respective biodiesel industries. Crude glycerol is the common byproduct from all the biodiesel industries irrespective of the biomass resource. All the components associated with the alternative biofuels industries should be sustainable for a well-balanced bioeconomy. Biorefinery concept is vital in moving towards a sustainable bioeconomy. This review highlights the research results, current status, opportunities, and challenges on engineering uses of the downstream products from biofuel industries as raw materials in the design and engineering of plastic resins, biodegradable plastics, bioadhesives, biorubber and biocomposites. These novel bioplastics and biomaterials can supplement and substitute certain petroleum-based plastics and materials. This means a tremendous reduction in green house gas emission through use of biobased products and sinking our dependency on petroleum for societal and environmental benefits.