Primary Bioresources

Bioresource

Bioresources are natural renewable sources like organic wastes and naturally formed or formable raw materials from human and animal activities.

Primary Bioresources

Primary bioresources are generated for a specific application-oriented purpose in forestry, agri- or aquaculture to enable the production of food, substantial products, or eventually energy (Figure 7.3). The utilization of primary bioresources for energy production is questionable due to efficiency issues.

Virgin primary bioresources are grown plants or animals mainly. Quantitatively, actually the most important primary bioresources are plants; from minor importance are cultivated algae, microorganisms, or fungi. To virgin primary bioresources count the whole harvested nonprocessed plant or the slaughtered animal, respectively.

Processed primary bioresources are generated in follow-up processing steps. There parts of the virgin primary bioresource are separated in order to gain the most value-added parts needed to produce the final “core product” of the utilization chain, e.g., food, paper, or bioplastic products. In primary processing the most value-adding parts are separated commonly with mechanical processing steps. Examples are the removal of major disturbing parts, e.g., twigs and branches from a tree to gain stemwood, or to separate straw from the crop to get grains. Other, more complex industrial processing steps follow focusing on the production of the anticipated core product.

Note: Not all plants can be considered as a primary bioresource. Examples are plants from parks and gardens which have primarily a recreational function. They are assigned to secondary or tertiary bioresources (Chapter 7, Section 2.2.3 and Section 2.2.4). The primeval forest plants are not primary bioresources either, because they are not grown for an application-oriented purpose. The same is true for wild living and pet animals.76 Primary bioresources are not considered as substrates for civilization biorefineries, but for the 1st, 2nd, and 3rd generation biorefineries. However, processing of primary bioresources should be closely connected within the system of a civilization biorefinery.

Introduction

Bioresources are natural renewable sources like organic wastes and naturally formed or formable raw materials from human and animal activities. In large quantities they are generated by industries or mills in the agriculture, forestry, marine, and municipal sectors. These bioresources feedstocks are taken by processing and manufacturing industries like the oil palm mills. Their bioproducts are made from agricultural plants and may be used as energy carriers, platform chemicals, or specialty products. There is huge potential for bioproducts in Malaysia and tropical countries from the forestry, agriculture, marine, and municipal sectors. In bioproduct terms, these emerging industries are significantly different from conventional industries in that at the various sector levels, the nature and characteristics of the feedstocks, products, and applications are diverse. The sustainable carbon lifecycle as depicted in Figure 8.1 shows the continuous process of carbon mass transfer into various states of utilization. Energy input from the sun is taken into the carbon cycle, which processes it for food, energy, and materials depending on the requirements of the country.

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Figure 8.1. Sustainable carbon lifecycle for food, energy, and materials production.

The bioproducts industry consists of the following sectors: the suppliers of the raw bioresources, manufacturing, and product users. In order to be viable, the bioresources must either have adequate quantities for a long-term basis or production of bioresources in large quantities must be available sustainably. The manufacturing industry must use a conversion process that is based on the best technology, is economically viable, is a sustainable process, and is environmentally friendly. Bioresources in the context in this chapter refer to biomass, organic solid wastes, carbonaceous solid wastes, and agricultural wastes. Most of the research in this chapter deals with solid wastes that are homogeneous in nature rather than heterogeneous wastes due to the handling nature and environmental constraints.

Biomass is gaining increased attention as it is one of the most available renewable energy resources for reducing dependency on fossil fuels. Agricultural wastes are categorized as biomass, and are generated continuously in enormous amounts from agricultural activities. Some of these agricultural wastes are utilized as fuel to generate the heat and electricity required for milling processes. The utilization of biomass for energy conversion is still considered limited due to its poor fuel properties such as high moisture and ash contents, low bulk density, low energy content, and difficulty in storage, handling, and transport. The excess biomass generated not only causes disposal problems but is also considered as a waste of primary resources.

The use of biomass as a renewable energy source is important for countries where there are limited supplies of fossil fuel reserves. The generation of these solid wastes from urban and agricultural sectors is increasing due to the industrialization activities of urban and rural development. The utilizations of biomass or carbonaceous solid wastes from industries for energy and value-added products have contributed to the provision of national energy as well as current and future materials supply. Biomass is the only renewable source of carbon, which is the basic building block for the energy, materials, and chemical industries.

Concluding Remarks and Perspectives

Bioresource use in the forms of new and waste biomass is a great opportunity and a challenge for the future since it offers the chance of replacing fossil fuels for the production of energy carriers, materials and specialty chemicals and diminishing the market pressure in an almost carbon-neutral way. Industrial biorefineries are seen as one of the most promising directions toward a sustainable bio-based economy. Fully developed biorefineries combine biological and physicochemical processes.

A weakness of biorefineries as an alternative to conventional oil refineries consists in the fact that the former is based on biofeedstock, which can require an intensive cultivation and land use.

Moreover, biorefineries could compete with food requirements and needs, which would limit the land allocated to biomass for biorefineries. As a result, the future of biorefineries should consider the use of nonedible biomass and the advanced processing of biomass waste, as well as land which could not normally be used for agriculture. This type of land could be used for microalgae cultures or renewable plants. Other sources of raw material for biorefineries could be found on waste from the food industry and urban organic waste. The processing of this raw matter can be successfully and eco-efficiently carried out through the development of enzymatic systems and engineered microorganisms capable of separating useful compounds from waste.

The development of these technologies should also consider the important issue of costs, since, currently, oil-based refineries offer more cost-effective solutions at the expense of environmental degradation and pollution.

Cellulose Dissolution

Cellulosic biomass is the most abundant bioresource produced on earth. In view of a perpetual supply of food, converting edible food into fuel is out of the question in spite of the easiness of producing bioethanol from starch. The process of producing biofuel from inedible biomass has been developed for the purpose of preserving edible food. Use of ubiquitously available cellulosic biomass should be a key strategy for supplying sustainable energy. The polysaccharides contained in biomass are insoluble in water owing to their intra- and intermolecular hydrogen bonding. Moreover, polysaccharides exist as supramolecular complexes in nature that are almost impossible to dissolve in water at the molecular level; thus, they are not easily extracted from biomass under mild conditions. In order to realize the bioenergy conversion with minimum consumption of energy, implementing the following steps is especially important: (1) dissolution and extraction of cellulose from biomass; (2) depolymerization of cellulose to glucose or oligosaccharides; and (3) energy conversion of these saccharides to generate electrical energy. In any process to generate energy from the biomass, the energy consumed should be kept as low as possible. At present, the energy needed to generate energy from polysaccharides is greater than the total energy yielded.

Biobased resin systems

The biobased polymers or biobased plastics are a group of materials derived from bioresources, as opposed to fossil fuel-based polymers. Source materials for the biobased composites can come from food industrial waste (Yu et al., 1998). Biobased plastics can be biodegradable under weathering conditions and degraded by microorganisms (Domenek et al., 2004). Biobased origin may not be equivalent with biodegradability. Therefore, NFC fibre reinforcement is intrinsically biodegradable, but the biobased resin may not be (Zini and Scandola, 2011). Bioplastics can be synthesized by microorganisms and have increased biocompatibility (Witholt and Kessler, 1999; Luengo et al., 2003).

Existing biobased polymer systems have relatively poor mechanical properties, such as polylactic acid (PLA), polyhydroxyaldehyde, polyhydroxybutyrate, polyester TP, furan resin and epoxy resins (Wool and Sun, 2005). The main applications for the biobased polymers are in the packaging industry and insulation, which are mainly thermoplastic polymers.

The development of new thermoset biopolymers with the enhanced mechanical properties, such as phenolics, epoxy, polyester and polyurethane resins, makes other applications possible (Raquez et al., 2010). Thermoset biopolymers can be reinforced with natural fibres to create a fully bioresourced composite (Mehta et al., 2004). Plant-based polymers, including proteins (Domenek et al., 2004), oils, carbohydrates, starch (van Soest et al., 1996) and a cellulose, have all been attempted.

In order to improve mechanical properties, partially biobased resin systems have been developed. They combine two or more resin systems where at least one is biobased, such as triglyceride acrylate (Cogins, Tribest S531), epoxidized pine oil waste (Amroy, EPOBIOX™), unsaturated polyester resins from renewable and recycled resources (DSM Palapreg® ECO P55-01, Ashland Envirez®) and soy oil unsaturated polyester (Reichhold, POLYLITE 31,325-00) (Shoseyov et al., 2011). Processing techniques used for biopolymers are usually similar to those for synthetic polymers.

An increase in global fossil fuel prices led to an increased interest in biosources of polymers. Nevertheless, the cost of biobased resin systems is still relatively high. In some cultivation areas the production of plant oils for industrial applications can compete with food production. Cultivation area shortages, together with the increasing global population, led to the increased research in a sea plant and microorganism sources for biopolymers (Mironescu and Mironescu, 2006; Kakita et al., 2003)

Enzymatic hydrolysis

Rice straw is a byproduct of rice production and is considered as a promising bioresource for ethanol production. In a research study, rice straw was used for the production of cellulose with an alkaline pretreatment and delignification, to remove lignin from cellulose which is utilize for the enzymes which permit the yeast to produce ethanol while utilizing glucose. Bioconversion provides an economical, safe, and reliable method for disposal of agricultural residues by solid substrate fermentation of rice straw under optimum conditions. In addition, it can also convert the lignocellulosic wastes into usable forms such as enzymes and reducing sugars that can be utilized for ethanol production. This enzyme system effectively leads to the enzymatic conversion of ultrasonic and acid pretreated cellulose from rice straw into glucose, and then into ethanol. These results also aid in the reduction of environmental air pollution, which is caused by burning of agricultural residues being burnt in the field. It was also observed that the process of acid pretreatment combined with ultrasound and following enzyme treatment results in the highest conversion of lignocellulose in rice straw to sugar and, subsequently, the highest ethanol production after 7 days of fermentation with Saccharomyces cerevisae yeast [71].

Another research study showed pretreatment of sugar cane bagasse using steam explosion in a specially designed reactor. The main goal of this study was to come up with a feasible technology for the conversion of the cumulative biomass of sugarcane into useful products. Biomass feedstocks such as bagasse and straw, including its lignocellulosic fraction, were converted into bioethanol fuel, with intensification of production. Therefore, circumventing the extension of the sugarcane fields for this methodology results in increased productivity in the most competitive settings, plummeting risks associated with economics and the environment, which will also increase the accessibility of economic and competitive ethanol to the market. Researchers plan to use agricultural crop residues including wheat and rice straw, corn stover, generated from citrus processing, grasses, coconut biomass, and residues from the pulp and paper industry (paper mill sludge), as well as municipal cellulosic solid wastes, which will ultimately also be utilized as raw materials in bioethanol production .

Linoleum—a natural composite

Linoleum is a good example of a natural composite. Without trying to breakdown bioresources into their chemical constituents as biopolymers do, linoleum simply combines natural materials to make a new composite. Furthermore, this discussion of linoleum should be contrasted with the earlier discussion of PVC-based vinyl flooring (see Chapter 7), given that both provide almost identical flooring solutions.

Linoleum was invented in 1860 by Frederick Walton, and was the first form of resilient flooring to replace more traditional bare wood or dirt floors (Lent et al., 2009). It is made by mixing oxidized linseed oil with resins from pine trees, wood flour, cork, and limestone fillers, with added pigments, which are then pressed onto a cloth backing to make sheet linoleum (Lent et al., 2009). These are natural and renewable materials (Akovali, 2012a). This general formula has remained largely unchanged since linoleum was first made (Lent et al., 2009). However, during the 1960s, vinyl flooring rapidly overtook the use of linoleum as the predominant resilient floor covering (Lent et al., 2010). The last US linoleum plant closed in 1975 (Lent et al., 2009, p. 14) and by the mid-1980s only three linoleum producers were left in the world (BBC, 2014). The most enduring and largest by volume manufacturer of linoleum, Fabro (previously Nairn in Kirkcaldy, Scotland) manufactures linoleum under the brand name Marmoleum (Anon., 2013).

More recently, with the recognition of the health and environmental concerns associated with vinyl there has been an upsurge of interest in linoleum (Lent et al., 2009). In 2009, Lent, Silas, and Vallette conducted a comprehensive review of the available resilient floor coverings for the Healthy Building Network, and recommended linoleum as either already better than all other alternatives or most able to be improved. Their research and similar comparisons show some possible concerns associated with linoleum. Because oxidation of linseed oil is at the core of the process, while the flooring is new, this oxidation can continue, leading to persistent odors (Lent et al., 2009). Recently, the VOC emissions of linseed-based paints have also been investigated, showing that a number of aldehydes are produced in the early hours and days post application (Fjällström et al., 2002). In one State of California study, two linoleum products failed Californian strict standards due to high emissions of acetaldehyde (Lent et al., 2009). However, this is not an unavoidable problem, but rather indicative of the relative neglect of research into improving linoleum production during the second half of the 20th century. Not all samples of linoleum suffer from the same problems and by developing new combinations of linseed and other oils this chemistry can be significantly improved (Fjällström et al., 2002; Lent et al., 2009). Similarly, farming of flax (linseed) as a crop has been associated with the use of environmentally persistent pesticides (such as trifluran) and eutrophication, both of which are avoidable through improvements in farming practices (Lent et al., 2009). Linoleum is also biodegradable.

The conclusion of this analysis is that linoleum should be reasonably healthy for users and neutral in impact for the environment, although it is important to research specific linoleum products, as these vary on both levels. In returning to the unavoidable comparison with PVC-based vinyl flooring (see Chapter 7), it is clear that a more natural and healthier alternative has always existed. While vinyl dominated the market because of its lower price and greater compositional predictability, and quickly worked its way into some regulations, leading to commonly perceived advantages in using it (Petrović et al., 2016), these benefits are in part negated because of the toxic chemicals used in its manufacture, toxicity release while in use, and the still only partly understood toxicity at the disposal stage (Section 9.4 and Chapter 7). Seen in that light, linoleum offers advantages well beyond those of vinyl flooring.

Limitations and prospects of hydrothermal liquefaction

The HTL of biomass and microalgae in the presence or absence of a catalyst can be implemented to convert the abundant bioresources into bio-oils for an efficient energy/fuel production technology. This technology is expected to provide more advantages compared to other bio-oil production technologies, such as pyrolysis or torrefaction processes.62,63 However, several drawbacks, such as inability to scale-up, need to be considered.

The requirement for highly advanced apparatus, such as reactors, is one of the limitations of this process because the reaction is operated under high temperature and pressure. In particular, operating under an atmosphere of reducing gases, such as hydrogen, can significantly stabilize the catalyst life span and increase the production yield. Nonetheless, the product cost will be increased due to the additional cost of the hydrogen itself and the related facilities. In addition, the formation of coke, tar, and solid residue during the process may block the functioning of the equipment. The bio-oils, after water separation, still contain several complex components and low quality. Thus intensive development in bio-oil upgrading or purification techniques is needed for the practical use of HTL bio-oils as fuels and chemicals. Process intensification and optimization are key factors for developing HTL of raw or pretreated biomass from a bench- or a pilot-scale process to industrial-scale applications. Thus it is crucial to develop multifunctional catalysts with excellent performance and long lifespans in order to enhance the energy efficiency, product quality, and minimize both the operating and capital costs of the HTL process.

Bioenergy production from second- and third-generation feedstocks

F. Dalena, ... A. Basile, in Bioenergy Systems for the Future, 2017

Abstract

This chapter aims to provide an update of the state of art of existing feedstocks for biofuel production from lignocellulosic biomasses. Lignocellulosic biomass is considered an important bioresource that can be utilized in many forms. In function of the nature of this lignocellulosic biomass, it is possible to make a difference between three feedstock generations. In the first one, the substrate consists mainly of seeds, potato, and grains, and the production process consists in the purification of simple sugars to obtain ethanol. But, the first-generation biofuels have been perceived as unsustainable from both an environmental and an industrial production cost points of view. So, the research has switched to the development of more advanced biofuels. For this reason, the first-generation feedstocks have been replaced in a first time by a second one (mainly agricultural wastes) and in a second time with a third one (algae). This chapter presents a critical analysis of published data on both the applications and potentiality of the bioenergy production from second and third generation of feedstocks.

A1: Raw material supply

Bio-based building materials can be made from several resources. Wood is one of the main bio-based materials used in the world, but several other bioresources are also used in construction, for example, bamboo, corn residues or sheep wool. We can separate them in two main categories: forest products and agriculture/animal products. Additionally, additives (mainly glues, coatings and preservation substances) from a bio-based or from fossil sources can be used for producing building materials (e.g. glues for particle boards, matrices for wood-plastic composites or preservatives for impregnated wood). Finally, recycled bio-based material can be used as raw material for bio-based building (e.g. recycled paper or solid wood).

Forest products. For the production of raw materials derived from forests, such as wood, cork or bamboo, a number of operations are carried out during forest management activities that originate environmental impacts (van Dam and Bos, 2004; van der Lugt et al., 2006; Dias and Arroja, 2012; González-García et al., 2013). The burning of fossil fuels in mechanised operations (e.g. cleaning, thinning, pruning or harvesting) generates air emissions such as carbon dioxide (CO2), sulphur dioxide (SO2) and nitrogen oxides (NOx), which contribute, for example, to climate change, acidification and formation of photochemical oxidants. Fertiliser application may cause eutrophication due to nutrient release to the environment and can contribute to climate change as a result of nitrous oxide (N2O) emission to the atmosphere. The application of pesticides may lead to toxicity-related impacts. Other impacts associated with land use may also arise such as changes in soil organic carbon and fertility, biodiversity, erosion and water use. On the other hand, forest ecosystems have the capacity to uptake CO2 from the atmosphere and store this carbon in living (stemwood, branches, foliage and roots) and dead biomass (litter, wood debris and soil organic matter), which is an environmental benefit.

Agriculture and animal products: Global land use is characterised by competition between food, fuel and feed production. There are higher risks for indirect land-use change (ILUC) and the associated environmental impacts for agricultural production. For example, biofuel production typically takes place on cropland, which was previously used for food production. Since this agricultural production is still necessary, it may be partly displaced to previously noncropland such as grasslands and forests. This process is known as indirect land-use change (ILUC). ILUC risks negating the GHG savings that result from increased biofuels because grasslands and forests typically absorb high levels of CO2 (European Commission, 2012).

Many products from agriculture and livestock husbandry can be used as raw material in buildings. Amongst them are straw, flax, sugar cane bagasse, corn, hemp, rice husk, groundnut shells, kenaf, reed, sheep wool, casein and polylactic acid (PLA) (Schmidt et al., 2004; Ardente et al., 2008; Murphy and Norton, 2008; Menet and Gruescu, 2012; Silva et al., 2014; Chaussinand et al., 2015; Palumbo, 2015). Conventional agricultural processes need fuel, fertiliser and pesticides similar to a forestry processes. Besides this, land use and soil preparation can be intensive and can lead to degradation of the soil leading to natural resources loss. Agricultural processes are responsible for emissions and environmental impacts in the same way as forest products. But for the cultivation of crops, fertilisers, pesticides, fuels and machine, utilisation is higher due to the annual cycles of cultivation. dos Santos et al. (2014) showed that the production of bagasse was the most relevant flow for eutrophication in an LCA of particle board due to the utilisation of fertilisers. The same observations were made by Ganne-Chédeville and Diederichs (2015) for the production of PLA contained in ultralight particle boards. Some crops need a high amount of water for irrigation. Intensive use of water for growing crops can lead to reduction of fresh water availability, which accounts as natural resource depletion. To a greater extent, it can also lead to ecotoxicological effects, by concentration of pollutants and biodiversity loss. Some bioresources can be directly collected from nature, for example, reed grass growing naturally in wetlands for roofing thatch. This avoids environmental impacts due to fertilisation and use of pesticides. The environmental impacts of animal hairs, mainly sheep wool, have been extensively assed (Henry, 2012). The major impacts of wool production are methane (CH4) emissions from sheep farms, which contribute to climate change and water consumption of the wool treatment processes. Other impacts are due to growing of biomass for feeding the sheep (impacts of agricultural products) and the energy and fuels used in the farms and for the wool treatments (mainly CO2, SO2 and NOx emitted). Agriculture and animal production systems have a lot of coproducts that are the basis for bio-based building materials. For example, meat and wool are two coproducts of the sheep production system. Environmental burdens of the coproduct are attributed mostly through economical allocation but sometimes also through mass allocation (Biswas et al., 2010; Jones et al., 2014).

Additives. Depending on their composition, manufacturing process and if they are produced out of fossil or bio-based sources, additives can have relevant environmental impacts even if they are used in small quantities. Preservatives are additives often used to extend the service life of bio-based building materials. Oil-borne preservatives such as creosote or water-borne preservatives such as copper or boron-based solutions are common for wood preservation (Hill, 2006). Processes of distillation and pyrolysis go through the combustion of fossil fuels or biomass, contributing to climate change, acidification, photo oxidation and resources depletion. In the case of metal-based preservatives (e.g. copper), raw material collection needs mining activities (loading, hauling, crushing and grinding), which are responsible for abiotic resource depletion, land use as well as air pollution (emissions of particles) and global warming potential due to fuel usage (Norgate and Haque, 2010). The production of petrochemical, mainly synthetic binders and plastics (e.g. urea-formaldehyde, polyurethane, melamine, polyethylene, polyester or phenolic resins), is responsible for fossil resource depletion and often needs high amounts of input energy as fossil fuels, which lead to CO2 emissions and contribute strongly to climate change (Rivela et al., 2005; Werner and Richter, 2007; González-García et al., 2009; Wilson, 2009; Silva et al., 2014; Sathre and González-García, 2014; Ganne-Chédeville and Diederichs, 2015). On the other side, bio-based additives, for example, tannin (Pizzi, 2008), corn starch, rubber, PLA (Ganne-Chédeville and Diederichs, 2015), sodium alginate (Palumbo, 2015), proteins, linseed oil or other natural extracts from plants and trees, can be used. Even if they are based on renewable resources, they also need to be grown, harvested (see environmental burdens of forest and agricultural products), processed, extracted or treated, which lead mostly to environmental burdens linked to emissions of energy production and consumption.

Recycled products: Recycled products are interesting alternatives for reducing the environmental impact of raw materials. Only the environmental burden linked to the manufacturing of these products that are not included in the module C3 (waste treatment/preparation for recycling) is to be accounted in an LCA of the products (EN 15804, CEN, 2012b). If the product can directly be reused without transformation (e.g. reuse of a wood beam), no environmental impact should be attributed to the raw material phase. But some products need to be transformed in order to be reused. For example, recycled paper process includes water and chemical consumption, heat and mechanical treatment operations (Arena et al., 2004). This process is responsible for environmental impacts like fresh water depletion, water ecotoxicity, climate change, acidification and photo oxidation.