Halophytes as Feedstock for Biogas Production: Composition Analysis and Biomethane Potential of Salicornia spp. Plant Material from Hydroponic and Seawater Irrigation Systems

Abstract

The halophyte plant species Salicornia europaea and Salicornia ramosissima were investigated for their potential to serve as a substrate for biogas production. Salicornia europaea was cultivated in hydroponic systems under varying salt concentrations (0, 10, 20, and 30 g/L NaCl), while S. ramosissima was grown in greenhouse farming with aquaculture effluent irrigation. The biomethane potential of the two halophyte feedstocks was determined through batch experiments, and correlations to the plant biochemical composition were investigated. Ash and mineral content of S. europaea was correlated to the increasing salt concentration used for plant cultivation in hydroponic systems. No indication of inhibition of the anaerobic digestion process was detected for sodium concentrations of up to 2400 mg/L in the anaerobic batch-test assays. The highest biomethane yield of S. europaea of 250 mL CH4/gVS was obtained when grown under 20 g/L NaCl and up to 300 mL CH4/gVS for S. ramosissima. By concentrating the dry matter content, the biomethane yield per ton of feedstock could be increased from 24 m3 CH4/t of the fresh halophyte plant to 74 m3 CH4/t by fractionation into a pulp fraction and to 149 m3 CH4/t by drying of the plant at room temperature for 1 week.

Bioactive Extracts from Salicornia ramosissima J. Woods Biorefinery as a Source of Ingredients for High-Value Industries

“…Considering this, biogas and bioethanol production from Salicornia spp. fibres and juice have been previously assessed [ 11 , 31 ].…”

A novel biorefinery concept based on marginally used halophyte biomass

“…[30][31][32] Other applications of S. ramosissima have been recently studied including as a source of cosmetics, 33 kitchen salt, 34 antioxidants 35 and biogas. 26 In this study, we have evaluated the application of S. ramosissima residual bers, a by-product of the juicing process applied for the extraction of bioactive compounds. To determine the potential of this plant residue in a biorenery context, parameters related to fractionation and downstream processing of samples have been assessed, and structures and components found in the lignin and hemicellulose fractions have been characterized.…”

“…30–32 Other applications of S. ramosissima have been recently studied including as a source of cosmetics, 33 kitchen salt, 34 antioxidants 35 and biogas. 26…”

Enhancing the Methane Yield of Salicornia spp. via Organosolv Fractionation as Part of a Halophyte Biorefinery Concept

“…Furthermore, the residual organic matter of the halophyte biomass can be used for renewable energy production in the form of biogas via anaerobic digestion (AD). However, AD of halophytes faces primarily two challenges: the high salt content that can inhibit microorganisms involved in the AD process, and the presence of lignin in the fibrous organic matter that reduces the rate and extent of hydrolysis in the microbial degradation process [4,5]. Lignocellulosic biomass comprises cellulose and hemicellulose bound to lignin by hydrogen bonds and ester-ether bridges, thus making the biomass recalcitrant in nature [6].…”

“…This makes green halophytic biomass more amenable to AD, with a higher degradability and higher methane yields. Nevertheless, the composition of halophytic biomass with respect to the lignocellulosic fiber material may vary depending on the species, location, and growing conditions [2,5].…”