Utilizing grass for the biological production of polyhydroxyalkanoates (PHAs) via green biorefining: Material and energy flows

Abstract

The meat and dairy industry across Europe is dependent on the production of grass. However, faced with competing pressures to reduce the environmental impact of agriculture, a potential future reduction of meat and dairy consumption in western diets, and pressure to minimize food production costs, grass could be used to produce alternative products. The biological production of polyhydroxyalkanoates (PHA) by using grass as the primary carbon source in a novel mixed culture process has been studied. A total of 30,000 t of fresh grass would yield approximately 403.65 t of dried biopolymer granules. On the basis of this early stage, non‐optimized process, the cumulative energy demand (CED) of PHA produced from waste grass and cultivated grass was found to be 248.4 MJ/kg and 271.8 MJ/kg, respectively, which is the same order of magnitude as fossil‐carbon‐based polymers. Improvements in volatile fatty acid yields, reduction in chemical and water inputs, and using residues to make other products will reduce the CED. Given the future requirement to produce polymers with little or no fossil‐carbon feedstock, an optimized version of the process could provide a viable future production option that also contributes to the long‐term sustainability of agricultural communities.

Readiness for Innovation of Emerging Grass-Based Businesses

“…Varied technologies to enhance the treatment and valorization of grass biomass unto high-value-added products for emerging markets have been studied and developed [10,12]. Yet, currently most of the technologies for utilizing the grassland biomass are developing at the lab scale and the further development, optimization and integration of the technologies into the existing industries or sectors are needed.…”

“…Utilizing the surplus material of otherwise unused grasslands can help valorize and maintain the biodiversity and ecosystem value of grasslands [6]. In the last few decades, varied technologies to enhance the treatment and valorization of grass biomass into high value-added products for emerging markets have been studied and developed [9][10][11][12]. However, the transfer of technologies and therewith commercialization of grass-based products into the market remains a difficult endeavor [13,14].…”

Polyhydroxyalkanoates Production: A Challenge for the Plastic Industry

“…Schematic representation of the location of diverse feedstocks with potential use as low-cost carbon sources for the production of PHAs. ,− …”

Intensification of Acidogenic Fermentation for the Production of Biohydrogen and Volatile Fatty Acids—A Perspective

“…This is especially true when considering the diverse, growing markets for VFAs, including disinfection, herbicides, bleaching, the food industry, the textile industry, pharmaceuticals, fungicides, polymer production, cosmetics and lubricants [207]. Given the increasing demand for bioplastic production and the finite nature of fossil fuels, PHA production is of particular interest here with recent research [237], demonstrating through life cycle analyses that the cumulative energy demand of PHAs produced using VFAs from an early stage, non-optimised grassfed bioreactors are in the same order of magnitude as deriving polymers from fossil fuels.…”