Lignins Isolated via Catalyst-Free Organosolv Pulping from Miscanthus x giganteus, M. sinensis, M. robustus and M. nagara: A Comparative Study

Abstract

As a low-input crop, Miscanthus offers numerous advantages that, in addition to agricultural applications, permits its exploitation for energy, fuel, and material production. Depending on the Miscanthus genotype, season, and harvest time as well as plant component (leaf versus stem), correlations between structure and properties of the corresponding isolated lignins differ. Here, a comparative study is presented between lignins isolated from M. x giganteus, M. sinensis, M. robustus and M. nagara using a catalyst-free organosolv pulping process. The lignins from different plant constituents are also compared regarding their similarities and differences regarding monolignol ratio and important linkages. Results showed that the plant genotype has the weakest influence on monolignol content and interunit linkages. In contrast, structural differences are more significant among lignins of different harvest time and/or season. Analyses were performed using fast and simple methods such as nuclear magnetic resonance (NMR) spectroscopy. Data was assigned to four different linkages (A: β-O-4 linkage, B: phenylcoumaran, C: resinol, D: β-unsaturated ester). In conclusion, A content is particularly high in leaf-derived lignins at just under 70% and significantly lower in stem and mixture lignins at around 60% and almost 65%. The second most common linkage pattern is D in all isolated lignins, the proportion of which is also strongly dependent on the crop portion. Both stem and mixture lignins, have a relatively high share of approximately 20% or more (maximum is M. sinensis Sin2 with over 30%). In the leaf-derived lignins, the proportions are significantly lower on average. Stem samples should be chosen if the highest possible lignin content is desired, specifically from the M. x giganteus genotype, which revealed lignin contents up to 27%. Due to the better frost resistance and higher stem stability, M. nagara offers some advantages compared to M. x giganteus. Miscanthus crops are shown to be very attractive lignocellulose feedstock (LCF) for second generation biorefineries and lignin generation in Europe.

Simultaneous Production of Cellulose Nitrates and Bacterial Cellulose from Lignocellulose of Energy Crop

“…The overview of the world literature on alternative cellulose sources has demonstrated that despite the diversity of Miscanthus species and their habitats [ 47 , 48 , 49 , 50 , 51 , 52 , 53 ], as well as their wide applications ranging from paper industry to biosynthesis products [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ], the information on Miscanthus cellulose as the substrate for chemical functionalization into CN is presently quite limited, except for the authors’ single studies.…”

Review of Current Prospects for Using Miscanthus-Based Polymers

“…The simplest energetic application of the Miscanthus biomass is the manufacture of fuel pellets. The studies [ 37 , 38 , 39 ] show that the Miscanthus pellets have a lower environmental impact compared to the wood ones, mainly because of less energy consumption during granulation: 1 ton of the Miscanthus pellets produce a carbon footprint of 121.6 kg CO 2 -eq., which is about 8% lower than that of the wood pellets [ 49 , 50 , 51 ]. In order to enhance the heating value, transgenic Miscanthus lines with enhanced lignin content were derived [ 52 ].…”

“…Up to 40 tons dry biomass a hectare per annum [22,23] ial crop Single planting Plantation operates for 20-25 years [12,36,37] agricultural practices…”

Sinking Our Teeth in Getting Dental Stem Cells to Clinics for Bone Regeneration

“…Therefore, research activities are directed toward the exploitation of renewable resources not used as food and feed source as well as biomass waste [485]. A broad variety of crop genotypes is under current investigation, among them so-called low-input crops cultivated in arid conditions [486][487][488][489]. Promising data are reported for lignin-based hydrogels and hybrid materials tested regarding their antimicrobial activity [490].…”