Bioconversion of Giant Cane for Integrated Production of Biohydrogen, Carboxylic Acids, and Polyhydroxyalkanoates (PHAs) in a Multistage Biorefinery Approach

Abstract

A highly productive Arundo donax L. clone (Clone AD-20) was produced at full field to give 54.6 Mg total solids biomass Ha–1. Biomass was chemically and enzymatically pretreated, recovering 13.9 Mg Ha–1 of glucose and 3.6 Mg Ha–1 of xylose, i.e., 3.5–4.5 more than yield typically obtained from corn stover or switchgrass. The subsequent fermentation of the liberated sugars to organic acids (OA) by dark fermentation generated yields of 3850 Nm3 Ha–1 of biohydrogen and 14.2 Mg Ha–1 of OAs. OAs were then used as a feed to produce polyhydroxyalkanoates (PHA), with 3-hydroxybutyrate the major monomer present (PHB > 95% PHA), from a biological process using mixed microbial culture producing 5.04 Mg Ha–1 of PHA. An initial economic analysis indicated that this multistage biorefinery approach would result in a net revenue of 10,415 € Ha–1, which is approximately 9-fold greater than that obtained by a traditional biorefinery producing bioethanol.

Recovering PHA from mixed microbial biomass: Using non-ionic surfactants as a pretreatment step

“…The system was calibrated with the polystyrene (PS) narrow standard of known Mw, polydispersity and intrinsic viscosity (Malvern PolyCAL PS standards -105kDa). A differential refractive index increment (dn/dc) value of 0.047 was used for further calculations [32].…”

The role of waste management in reducing bioplastics’ leakage into the environment: A review

“…PHAs are biodegradable polyesters characterized by physico-chemical properties not far from those of petroleum-derived plastics (Papa et al, 2020), and their main applications are represented by packaging and agricultural/medical goods production. Although PHAs production is actually limited by the high costs of substrates and the use of pure microbial cultures, several studies are focusing on the use of mixed microbial cultures to reduce costs, which should permit enhanced PHAs usage (Villegas Calvo et al, 2018). Since PHAs blends entered the market, the share of this biopolymer family continues to grow and production capacities are set to increase successfully almost seven times by 2025 (Table 1) (European bioplastic, 2020).…”

Polyhydroxyalkanoates (PHAs): Biopolymers for Biofuel and Biorefineries

“…In the crop-based synthesis approach of PHAs, a metabolically engineered system is established in one crop and, at the same time, generic technology is created which can be transferred to a different biomass crop. In this way, additional crops will be harvested and commercialized in different regions based on need [ 129 , 130 ]. The sugarcane industry was the first PHAs producing biorefinery.…”