This is a solution of Unit 2 Treatment On Solid Pineapple Waste in which we discuss Developing business
Pineapple Fruit Assignment Help
The pineapple fruit (Ananas comosus) derives from the Bromeliaceae family and is one of the most consumable fruit in the world (Atul et al., 2012). The pineapple grows mostly on peat soil but some are also grown on mineral soil. The pineapple fruit is processed in a variety of consumable products such as, juices, jams, pastries and many more. This directly leads to a large scale of pineapple plantations and pineapple based production. The amount of pineapple waste produced is abundant. See more : Consumers Buying Behavior And Related Theories
The pineapple waste mainly exists as solid and liquid state. The solid pineapple waste consists of several components such as the core, skin, and crown. The following is a diagram that shows the pomance (pressing) of fruits done generally in the fruit canned industry.
The solid pineapple waste are composed of several components, some of these are important and useful for the production of organic acid and in the involvement of fermentation. The solid pineapple waste has certain percentages of waste which thoroughly depends on the geographical origins, stage of growth and also the content of the pineapple component itself. The following is the diagram of the characteristics of pineapple waste.
The pineapple waste if pre-treated well can be utilized for various purposes such as agricultural feedstock and as a substrate for the production of organic acids and ethanol’s (Atul et al., 2012). The solid pineapple waste falls under the class of lignocellulose biomass.
The most potential renewable fermentable carbohydrate on earth is from the lignocellulose biomass. The plant based biomass is made up of 60% of lignocellulose. Lignocellulose is composed of cellulose, hemicellulose and a rigid structure of lignin. The lignocellulose is applied in various sources such as in the paper industry, bio fertilizers, chemical feed stock and also as animal feed stock (Tengerdy and Szakacs, 2003). The following is the diagram of a lignocellulose biomass.
Pre-treatment of lignocellulose waste is essential to obtain a good and quality end product. The lignocellulose is very well protected by two structure, which are the hemicellulose and lignin structure. An in proper pre-treatment or without pre-treatment can only lead to enzymatic hydrolysis to 20% maximum yield only (Bak et al., 2009). In order to obtain the maximum amount of enzymatic yield, a proper pre-treatment method is important to degrade the structure of lignin, at the very same time, these pre-treatment methods should not degrade or destroy the important components of fermentation, such as sugar, cellulose and hemicellulose. Read more : The plantation industry Assignment Help
In the lignocellulose biomass, the micro fibrils structure is made up of cellulose, hemicellulose and lignin. This structure intervenes the plant cells stability (Rubin, 2008). A very good pre-treatment will result in the removal and alteration of the structural in order to enhance the rate of enzyme hydrolysis, digestibility and yield product (Mosier et al., 2005).
Hemicellulose is a long branched polymer of C6 or C5 sugar or polysaccharide that consists. This structure of lignocellulose makes up about 20 to 30% of the whole structure. Hemicelluloses are easy to be hydrolysed due to their short, branched chains of several sugars. The type of sugar present in the chains of hemicellulose polymers are D-galactose, D-mannose, D-xylose, L-arabinose, 4-O-methyl-glucuronic D-glucuronic acids and D-galacturonic. These sugars are linked by b-1,3-glycosidic bonds and b-1,4-glycosidic bonds (Perez et al., 2002). Below is the chemical structure of hemicellulose.
Cellulose is a macromolecule of sugar which comprises 45% of the lignocellulose biomass. The cellulose structure exists as long chains of elemental fibrils. These long chains are bonded by van der Waals forces and hydrogen bonds. The polymers of this long chain are made up from cellobiose molecules where the b-1, 4 glycosidic bonds forming is linked by D-glucose subunits. Cellulose has a higher molecular weight then hemicellulose. Out of the three structures of lignocellulose, cellulose is more prone to enzymatic degradation (Beguin et al., 1994). Cellulose do exists as a crystalline form and thus could be affected by biodegradation. Figure 2.4 shows the structure of cellulose
Lignin is found entrenched between the structure of cellulose and hemicellulose. The structure of lignocellulose is generally agreed that the hemicellulose molecules are oriented parallel to the cellulosic fibrils as shown in Figure 2.6. It is usually found in the vital part of the cell wall (Perez et al., 2002). This structure is the most profuse structure among polymers. Instead of sugar polymers, the lignin is composed of aromatic polymers which are produced from phenylpropanoid as shown in Figure 2.5. Instead of sugar polymers, the lignin is composed of aromatic polymers which are produced from phenylpropanoid. The amount of lignin components relies on the type of the plants. Lignins are usually categorized into two which groups are guaiacyl syringyl lignin and guaicyl lignins (Gibbs, 1958).
Guaiacyl syringyl units are mostly present in the hardwood, where else in softwood, guicyl lignins are present. Research has been found that the lignin present in softwood is much tougher to be removed by alkaline treatment than hardwood (Ramos et al., 1992). This is due to the characteristics of fibre, which confines thus block the enzyme digestibility (Tanahashi et al., 1983). Lignin’s chemical structure could be altered under high pressure, temperature and acidic conditions (Hetti, 2004). Diagram of the lignin structure and the positions of cellulose, hemicellulose and lignin
Pre-treatment of Lignobiomass
Researchers have been developing the proper and refined pre-treatment methods for decades. The first pre-treatment method was developed in the 1920’s, starting from acid pre-treatment system (Saville, 2011). The ideal pre-treatment method is hard to be applied to all the biomass, due to their own unique properties. Thus, a variety of pre-treatment methods has been evolved. The overall ideal property of the results of a pre-treatment is refined universally. The properties are, a pre-treatment which does not degrade sugars, does not inhibit fermentation steps, produce a highly digestible pre-treated solid, produces no solid waste residues, able to work in reactors of moderate cost and reasonable size and is effective in low moisture content (Johnson and Elander, 2008).
The lignin is the most difficult structure to be removed from a lignocellulose waste. The purpose of the pre-treatment is to remove or degrade the lignin for a better access and exposure of hemicellulose and cellulose (Li et al., 2010). Below is the figure on the effect of pre-treatment.
Pre-treatment Effects on Cellulose
The pre-treatment method affects the cellulose in many ways. The pre-treatment method influences the particle size of cellulose, its crystallinity and the accessible of the cellulose surface area. The effect of pre-treatment at times leads to the recalcitrance in the enzymatic hydrolysis. The pre-treatment that involves the removal of lignin and hemicellulose impacts the cellulose fiber’s length, width and physico chemical property. The most common provenance of pre-treatment is the production of crystalline structure from amorphous cellulose.
The best pre-treatment method that is appropriate in terms of cellulose effect is the pre-treatment which produce the most little crystallinity of cellulose (Saville, 2011). The pre-treatment method that involves the enzymatic hydrolysis should be taken caution from the initial step starting from milling and drying which influence the surface area of cellulose (Kumar et al., 2009).
Pre-treatment Effects on Hemicellulose
The hemicellulose structure is highly composed of sugar polymers which have been explained in section 2.2.2. The crucial role of pre-treatment is to impact directly into the structure by disrupting the cellulose. This will aid in the enzymatic hydrolysis. The hemicellulose plays a vital role in forming the cell wall’s backbone structure. This is possible due to the presents of micro fibrils and lignin bonded through hydrogen bond (Saville, 2011).
Pre-treatment Effects on Lignin
The pre-treatment method effects lignin in various ways. Some pre-treatments lignify the structure, some causes the lignin to be modified. When the lignin is exposed to heat and pressure, solvents, acid and reagents, the lignin content would not remain intact. After pre-treatments lignin recoveries are highly possible. Lignin acts as a strong barrier which directly hinders cellulose and inhibits cellulose’s bindings (Saville, 2011). The application of surfactant helps in the development of enzymatic hydrolysis. The surfactant such as tween 80, works by inhibiting the lignin’s binding site (Chandra et al., 2007).
Methods of Pre-treatment
The methods of pre-treatments are generally divided into three main categories: the chemical pre-treatment, biological pre-treatment, and physical pre-treatment (Harvey et al., 2011).
These methods are classified based on the pre-treatment processes such as, pre-treatments that rely on biological organisms, chemicals, bases, acids and other solvents. Next the pre-treatments processes which involves pressure, mechanical energy and mostly heat. The last process relies on the sizing of the hemicellulose biomass. The following Table 2.2 explains the advantage and disadvantages of the pre-treatments of lignocellulose biomass.
The chemical pre-treatment involves in the interruption of the biomass structure by the means of chemicals. The chemicals used are either combined or singly used (Harmsen et al., 2010). In these pre-treatment, certain factors important factors are taken into consideration such as, the ratio of liquid and solid and pre-soaking which helps in the fair and sufficient distribution of the chemicals (Saville, 2011).
The acid pre-treatment are carried out in both dilute and concentrated solutions. The common acids which are used are sulphuric acid, phosphoric acid, nitric acid and hydrochloric acids. The most common dose ranges of dilute acids used in the pre-treatments are from 0.75 to 5 (v/v)%. The usage of the dilute acid is economical, due to its reuse property. The dilute acid has the possibility of retaining 100% of hemicellulose hydrolysis. The crystallinity of cellulose could be also reduced, which mean the cellulose is not much affected. The disadvantage of dilute acid is, high temperature needed at times, and this contributes to the destruction of cellulose and conversion of monomer sugars (Harvey et al., 2010).
In the concentrated acid hydrolysis such as hydrochloric acid and sulphuric acid is commonly used. The advantage of concentrated sulphuric acid is that it doesn’t decompose the sugar obtained and completely hydrolysis the hemicellulose. The percentage of sugar recovery reaches about 85% in recovery. The disadvantage of this is the sulphuric acid is hard to be recovered because the sugar and the acid are non-volatile.
Alkaline pre-treatments are well known for their degradation or removal of lignin. This directly leads to a good and high percentage enzymatic hydrolysis. The alkaline pre-treatment does not hydrolysis the hemicellulose structure (Hsu, 1996). The pre-treatment of alkaline solutions acts by swelling the fibers. This affects the lignin structure. The swelling also increases the surface area and reduces the formation of crystallinity and degree of polymerization. The structural bond between carbohydrates and lignin can also be broken down (Johnson and Elander, 2008).
The effectiveness of alkaline pre-treatment highly depends on the concentration of the solution. The most effective percentage range falls around 1% to 2 (w/v) % (Harvey et al., 2010). This concentration has recorded the highest amount of yield of reducing sugar.
The categorization of physical pre-treatment can be divided into two, the irradiation property and the comminution property. Prior to the pre-treatment, almost all the lignocellulose biomass must undergo size reduction. This depends entirely on the type of pre-treatment. The size degree of the milling has an important influence in assisting the pre-treatments. Various types of comminution have been applied in research project, starting from various types of milling, such as vibratory, wet and dry milling. These methods does play its part in increasing the enzyme digestibility, surface area and this also helps to reduce crystallizing of cellulose (Millet et al., 1979). Read more : Unit 2 Managing Financial Resources and Decisions Assignment
Researchers believe that the irradiation emitted from equipment, such as the microwave, interrupts the rigid structure of the cell wall. This method also helps in the reducing of cellulose crystallinity (Ooshima et al., 1984). The microwave pre-treatment has some good advantages compared to the other two. This include the change of cellulose structure, low energy requirements, the ability to control the flow of experiment, in terms of time control, and high recovery of total reducing sugar (Nomanbhay et al., 2013).
The usage of microwave radiation is a favourite due to its alternative way of heating compared to the conventional way (Hu and Wen, 2008). The microwave pre-treatment method contributes to different results on conditions if treated together with other solvents, such as alkaline solution.
Research has also shown that the combination of the microwave pre-treatment with the presence of water could help to increase the rate of hydrolysis of lignocellulose biomass (Azuma et al., 1984).
The microorganisms which are involved in the biological pre-treatment of lignocellulose are characterized as lignin solubilizing microorganisms. The most common and famous microorganism, is the white rod fungi. Bacteria also play its role in this pre-treatment, but the fungi have much more advantage and produce more enzyme (Hsu, 1996). In this pre-treatment the complex structure of the lignin can be degraded by the lignin degrading enzyme. The microbial organisms, such as the fungi, have the enzyme that degrades the tough lignin structure (Hamisan et al., 2009).
The enzymes exertion on the degrading of lignin breaks the plant cell wall. This leads to a better access to the cellulose complex (Zeng et al., 2011). The cellulase enzyme which is present degrades cellulose. This mechanisms is carried out by three groups of cellulase, which are β-glucosidase, β-1, 4-endoglucanase and β-1,4-exoglucanase. β-glucosidase produces glucose by cellobiose hydrolization, the β-1,4-endoglucanase produces free chain ends by attacking the crystalline region of the cellulose fiber. The final enzyme, β-1,4-exoglucanase removes cellobiose unit by further degrading them from the free chain.
The biological pre-treatment has several advantages compared to other two pre-treatment. The biological pre-treatment only consumes low energy, no complex equipment needed, and its economically safe (Keller et al., 2003). Among the white rot fungi used, the Phanerochaete chrysosporium has a very high impact on the lignin degradation (Pellinen et al., 1988).
Phanerochaete chrysosporium has been widely studied for degradation of lignin in biological pre-treatment. The activity of the fungi depends on few parameters such as the spore count, substrate moistures, temperature, basal media and pH level (Liwiki et al., 1985).
The spore count range used so far in the biological pre-treatment of lignocellulose waste range from (5 × 106 to 7 ×106) for the solid state fermentation (Hadar et al., 1993). The temperature range for the growth of this fungus is between 29°C to 39°C (Kirk et al., 1978). The range of moisture content that growth of Phanerochaete chrysosporium falls around 35% to 80% moisture content. Research has done regarding the moisture content and the highest lignin degradation is observed at moisture content of 75% and 80% (Shi et al., 2008).
Lactic Acid from Pre-treated Lignocellulose Biomass
The production of lactic acid from lignocellulose waste has recently received attention due to its vast and growing application in various industries. The lactic acid is especially focused in the application of biodegradable compound (Zhou et al., 1999). The production of lactic acid from pre-treated biomass highly depends on the yield sugar concentration of the pre-treated materials Lactic acid can be converted from sugars derivatives of glucose, sucrose, and fructose.
These sugars are recoverable from the pre-treatments of lignocellulose waste (Oh et al., 2005). The production of glucose from the pre-treated solid pineapple waste is essential for saccarification of lactic acid.
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