Birgit Kamm

Bio based fuels and fuel additives from lignocellulose feedstock via the production of levulinic acid and furfural.

Abstract The demand for biomass-derived fuels and fuel additives, particularly in the transportation sector, has stimulated intense research efforts in the chemistry of levulinic acid and levulinic acid secondary products over the past decade. Additionally, recent technological progress in lignocellulosic feedstock (LCF) chemistry has also increased attention in this regard. As a result, several oxygenating fuel additives with potential applications in both gasoline and diesel fuels have been identified. Some of the chemicals, such as ethyl valerate, appear to be viable alternatives to the currently used branched, short-chain ethers that are derived from side products of petrol refining. Cost-effective applications of lignocellulosic biomass are a crucial aspect of its feasibility. In consideration of the LCF biorefinery concept, the feasibility must also include the chemical pulping of LCF and the comprehensive utilisation of its main constituents cellulose, hemicelluloses, and lignin. The present study focuses on cellulose and hemicelluloses as viable sources for the production of biofuels and biofuel additives. Multifunctional catalysis, including hydrogenation and acid catalysis are the primary instruments used for the conversion of the monomeric carbohydrate building blocks, i.e., mainly C5 sugars, such as xylose and arabinose, and C6 sugars in the form of glucose and their respective secondary products, furfural and levulinic acid. Lignin utilisation is not addressed in this paper.

International biorefinery systems

The development of biorefineries represents the key for access to an integrated production of food, feed, chemicals, materials, goods, and fuels of the future [1]. Biorefineries combine the necessary technologies of the biogenic raw materials with those of intermediates and final products. The main focus is directed on the precursor carbohydrates, lignins, oils, and proteins, and the combination between biotechnological and chemical conversion of substances. Currently, the lignocellulosic feedstock (LCF) biorefinery, green biorefinery, whole-crop biorefinery, and the so-called two-platform concept are favored in research, development, and industrial implementation.

Biorefineries – their scenarios and challenges

Abstract Since crude oil and biomass differ in various properties, new primary fractionation methods of biomass, secondary conversion pathways and processes have to be developed. Biorefineries combine the necessary technologies of the biogenic raw materials with those of intermediates and final products. The chemical industry is experiencing a fundamental shift as cost competitive biobased platform chemicals become a commercial reality. The paper is focused on lignocellulosic feedstock and green biomass biorefinery concepts, which are favored in research, development and industrial implementation. The production of aromatic platform chemicals, such as furfural, hydroxymethylfurfural and derivatives as well as aliphatic platform chemicals, such as levulinic acid and formic acid is described. Futhermore, functional products, such as proteins and biotechnological produced platform chemicals are considered.

Microbial Life on Green Biomass and Their Use for Production of Platform Chemicals

This chapter describes the basics for the development of future biotechnology processes for the production of platform chemicals. Microbial life on green plants and harvested plants is very dynamic. Identified microorganisms on green plants and in silage as described in literature are listed in tables. But almost weekly new microorganisms are discovered, which constitute the site of a great variety of so far unknown metabolic pathways. Some microorganisms and their metabolic pathways to six organic acids used as platform chemicals and applications currently and in future are described.

Qualitative and Quantitative Analysis of Lignins from Different Sources and Isolation Methods for an Application as a Biobased Chemical Resource and Polymeric Material

Lignins in general have been extensively studied, though the relation between source, isolation method and application is rarely described. In the present work, lignin from different sources (wheat straw and beech wood) and isolation methods (steam explosion, Organosolv) has been characterized regarding their application as a chemical resource and polymeric material. A range of analytical methods were applied including elemental analysis, FT-IR, 31P NMR, SEC, Py-GC-MS and HPLC to gain information about establish the purity, structure, molecular weight, thermal behavior and to determine carbohydrate residues according to the NREL protocol. TGA and DSC were used to study the thermal behavior of the isolated lignins and showed relatively low glass transition temperatures around 120 °C and decomposition temperatures between 340 and 380 °C. NREL analysis presented a carbohydrate-free lignin fraction derived from beech wood via Organosolv process which has not been achieved to date. The finding of this work supports Organolsolv as an efficient method to isolate pure lignin fractions from beech wood with practical value in industry, in particular for application in polyurethanes and phenolic resins.

Chapter 3:The Biorefinery Concept – Thermochemical Production of Building Blocks and Syngas

Plant biomass always consists of the basic precursor: carbohydrates, lignin, proteins and fats, beside various substances such as vitamins, dyes, flavours, and aromatic essences. Biorefineries combine the essential technologies between biological raw materials and the industrial intermediates and final products. In this chapter, the lignocellulosic feedstock system, technologies and products are considered. In particular, focus is directed on the platform chemicals (building blocks) furfural, levulinic acid, hydroxymethylfurfural, sugar alcohols, and lactic acid obtained by thermochemical conversion methods, as well as synthesis gas. The article gives an overview over different production methods and several applications of these building blocks.

Lignin-Derived Biomaterials for Drug Release and Tissue Engineering

Renewable resources are gaining increasing interest as a source for environmentally benign biomaterials, such as drug encapsulation/release compounds, and scaffolds for tissue engineering in regenerative medicine. Being the second largest naturally abundant polymer, the interest in lignin valorization for biomedical utilization is rapidly growing. Depending on its resource and isolation procedure, lignin shows specific antioxidant and antimicrobial activity. Today, efforts in research and industry are directed toward lignin utilization as a renewable macromolecular building block for the preparation of polymeric drug encapsulation and scaffold materials. Within the last five years, remarkable progress has been made in isolation, functionalization and modification of lignin and lignin-derived compounds. However, the literature so far mainly focuses lignin-derived fuels, lubricants and resins. The purpose of this review is to summarize the current state of the art and to highlight the most important results in the field of lignin-based materials for potential use in biomedicine (reported in 2014–2018). Special focus is placed on lignin-derived nanomaterials for drug encapsulation and release as well as lignin hybrid materials used as scaffolds for guided bone regeneration in stem cell-based therapies.

Biorefining of Lignocellulosic Feedstock by a Modified Ammonia Fiber Expansion Pretreatment and Enzymatic Hydrolysis for Production of Fermentable Sugars

Wheat straw was pretreated and afterwards enzymatically hydrolyzed using a modified ammonia fiber expansion (AFEX) process under different reaction conditions to produce fermentable sugars. Instead of liquid ammonia, aqueous ammonia (25 % w/v) was used to test its influence on the sugar concentration and yield of the sugars. It is shown that a protein extraction after the pretreatment can distinctly improve the result obtained for the enzymatic hydrolysis. This modified AFEX process using aqueous ammonia represents a simpler and less expensive variant of the AFEX process usually described in literature. Thus, the described process can be used for the primary refining of lignocellulosic feedstocks in the sense of a roadmap for biorefinery.

Chapter 3:Primary Processing

Primary processing of oil-containing material involves pre-treatment processes, oil recovery processes and the extraction and valorisation of valuable compounds from waste streams. Pre-treatment processes, e.g. thermal, enzymatic, electrical and radio frequency, have an important effect on the oil recovery, quality of oil, extraction possibility and quality of valuable compounds from waste streams. Apart from these methods, dehulling, i.e. the separation of the coats from the seeds, can be regarded as a first and indispensable step. To extract and market proteins at an industrial scale, as long as water extraction remains in the domain of research and development, it will be necessary to dehull the seeds before oil extraction in order to extract the proteins and improve the valorisation of these crops. The state-of-the-art of the recovery of (residual) oil from olive, rapeseed and sunflower by-products is reported. The three crops are described with regard to structure, by-products from the oil production and the applied extraction methods. Alternatives for hexane extraction, such as water, iso-propyl alcohol, gas-assisted extraction or supercritical carbon dioxide extraction, could improve the potential of the different oil-bearing crops. The extraction of amino acids and/or protein fractions, which forms the main fraction in the press cakes is described. Also, the possibilities of the production of levulinic acid from the lignocellulosic parts of the crops are investigated.

Lignocellulosic Biomass for Energy, Biofuels, Biomaterials, and Chemicals

The main objective of this chapter is to explore the lignocellulose feedstock (LCF) biorefinery for industrial usage according to green chemistry principles. In particular, the isolation and valorization of lignin as one of the most interesting intermediates of LCF biorefineries is discussed, including lignin isolation, purification, and structure analysis. Structure elucidation involves various chromatographic, spectroscopic, microscopic, and thermochemical methods. Thus, basic structure–property relationships regarding the influence of biomass source and isolation process on lignin amount, constitution, and 3D structure are highlighted. Furthermore, storage effects on lignin structure and degradation effects are presented. Finally, potential applications are discussed, including novel lignin-based hydrogels, composite compounds (hybrids), and nanomaterials. Focus is drawn to antioxidant and antimicrobial activity of lignin for applications in packaging and biomedicine, that is, biomaterials for drug release and tissue engineering.