The kinetic study on hydrolysis of cellulose (saw-dust)

Thesis Overview

<p> </p><p><strong>1.1 INTRODUCTION</strong></p><p>Cellulose is a naturally occurring polymeric material containing thousands of glucose-like rings each of which contain three alcoholic OH groups. Its general formula is represented as (C6H10O5 )n. The OH-groups present in cellulose can be esterified or etherified, the most important cellulose derivatives are the esters. Cellulose is the name given to a long chain of atoms consisting of carbon, hydrogen and oxygen arranged in a particular manner. Cellulose is found in nature in almost all forms of plant life, and especially in cotton and wood. A cellulose molecule is made up of large number of glucose units linked together by oxygen atom. Each glucose unit contains three(3) Hydroxyl groups, the hydroxyl groups present at carbon-6 is primary, while two other hydroxyl are secondary. Cellulose is the most abundant organic chemical on Earth more than 50% of the carbon in plants occurs in the cellulose of stems and leaves. Wood is largely cellulose, and cotton is more than 90% cellulose. It is a major constituent of plant cell walls that provides strength and rigidity and presents the swelling of the cell and rupture of the plasma membrane that might result when osmotic conditions favor water entry into the cell. Cellulose is a fibrous, tough, water-insoluble substances, it can be seen in cell walls of plants, particularly in stalks, stems, trunks and all woody portions of the plant.2Cellulose is polymorphic, i.e there are a number of different crystalline forms that reflect the history of the molecule. It is almost impossible to describe cellulose chemistry and biochemistry without referring to those different forms. Cellulases are gotten from cellulose, cellulose is also found in protozoa in the gut of insects such as termites. Very strong acids can also degrade cellulose, the human digestive system has little effect on cellulose. The word cellulose means β-1,4-D-glucan, regardless of source because of the importance of cellulose and difficulty in unraveling its secrets regarding structure, biosynthesis, chemistry, and other aspects, several societies are dedicated to cellulose, lignin, and related molecules.</p><p><strong>1.2 SOURCES OF CELLULOSE</strong></p><p>Cellulose for industrial conversion comes from wood and scores of minor sources such as kenaf paper and rayon are now made mostly from wood pulp. cotton rings were historically important for paper making, and cotton linters (short fibres are used to spin yams) are now used in high quality writing and currency papers.Cellulose forms very tightly packed crystallites, these crystals are sometimes so tight that neither water nor enzymes can penetrate them; cellulose consists of two cellulose molecules;3 Crystalline and amorphous cellulose. The crystalline cellulose is insoluble because of the inability of water to penetrate cellulose, On the other hand amorphous cellulose allows the penetration of endoglucanase, another subgroup of cellulose that catalyze the hydrolysis of internal bonds. The natural consequences of this difference in the crystalline structure is that the hydrolysis rate is much faster for amorphous cellulose than crystalline cellulose.Some cellulose comes from the hairs (trichomes) on seeds, example: cotton, kapok and milkweed. A commercial bacterial cellulose product (celluon) was introduced by Weyerhaeuser(22) for use in foods, the product is called primacel and is available from Nutrasweet kelco. Recently, cellulose from sugar beet pulp and from citrus pulp has aroused interest for use as a fat substitute.</p><p><strong>1.3 HYDROLYSIS</strong></p><p>Hydrolysis of cellulose is the process of breaking the glycosidic bonds that holds the glucose basic units together to form a large cellulose molecule, it is a term used to describe the overall process where cellulose is converted into various sweeteners. Hydrolysis is a chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions, which may go to participate in further reactions.</p><p><strong>1.4 SUGAR</strong></p><p>Sugars (also called saccharides) are compounds containing an aldehyde or ketone group and two or more hydroxyl groups. Sugar can also a sweet crystalline substance obtained from sugar-cane and sugar beet. It includes sucrose, glucose and fructose.</p><p><strong>1.5 STATEMENT OF THE PROBLEM</strong></p><p>The clamour for the diversification of Nigerian economy through low quality products has motivated researchers to explore the numerous domestic, industrial and economic importance of one Nigeria`s major product (cellulose) which forms the bedrock of this project.Sugar is a commodity of high demand for both domestic and industrial applications on daily basis in homes, small and medium scale industries e.t.c. this is why Nigeria government spends huge sums of money on importation of sugar and sugar products to meet the demand of citizens. Among the many processes of sugar production, is acid hydrolysis of (cellulose) has proved to be a process which encourages the production of high quality with minimum skill and materials. This work is therefore an effort to encourage industrialists, researchers, and students to carry out more intensive studies on production of sugar from cellulose for production of sugar and enhanced economic resources for the nation.</p><p><strong>1.6 RELEVANCE OF THE STUD</strong></p><p>Nigeria is the largest producer of cellulose for which paper wood is made. A large percentage of produced cellulose is consumed as paper, textiles, newspaper and containers in form of writing, reading e.t.c.The method of acid hydrolysis of cellulose:<br>ï‚· It creates job opportunities, hence, reducing unemployment in the country.<br>ï‚· It helps to know the best acid for the hydrolysis of cellulose.<br>ï‚· It establishes the industries for government to contribute immensely towards the country economy.<br>ï‚· With the methods of glucose and cellulose production, the cost of glucose and cellulose will reduce.<br>ï‚· It produces research work done on the digestion of cellulose into glucose which I will engage on it after my graduation</p><p><strong>.1.7 OBJECTIVES</strong></p><p>The research project covers the processes, operations and pathways involved in the Acid hydrolysis of cellulose to produce (glucose) sugar. The research study aims at:6ï‚· Quantifying and calculating the yield of glucose from the hydrolysis of cellulose using two different acids.ï‚· The hydrolysis of cellulose into sugar using different concentration of hydrochloric acid and sulphuric acid.</p><h3>References</h3><p>Adas Michael J.E. and Ollis, D.F.1986, Biochemical Engineering Fundamentals, 2nd Ed., p163-172, McGraw-Hill.</p><p>Austin, G.T (1914), Shreve’s Chemical Process Industries (5th ed,) McGraw Hill, United State Pp 554-670.</p><p>Bailey, J.E, and Ollis, D.F (1986). Biochemical Engineering Fundamentals, 2nd ed, Chapter 3, McGraw Hill.pp 110-150</p><p>Bradbury J.H (2006). Simple Wetting Method to Reduce Cyanogens content ,” Journal of Food Composition and Analysis (Elsevier, New york) (4ed.) pp 388-398.</p><p>Brown, W.H and Poon, T.(2005), Introduction to Organic Chemistry (3rd ed), Wiley ISBN 0-47144451-0. Pp 550-650</p><p>Bertran, M.S. and Dale, B.E, 1985. Enzymatic hydrolysis and recrystallization behavior of initially amorphous cellulose, Biotech. Bioeng., 27, 177,</p><p>Eliasson A.N (2004). Starch in Food Structure, Function, and Applications Wood Head Publishing. ISBN 9780849325557.</p><p>Greenwood, N.N and Earnshaw, A (1997). Chemistry of the Elements (2nd ed) Oxford: Heinemann, ISBN 0080379419 pp 384.</p><p>Ghose, T.K., 1977, Cellulase biosynthesis and hydrolysis of cellulosic substances, in Advances in Biochemical Engineering, 6, 25, pp 345</p><p>Grethlein, H.E. 1985 , Comparison of the economics of acid and enzymatic hydrolysis of newsprint, Biotech. Bioeng, 20, 503, 1978. Erickson, L.E., Energetic efficiency of biomass and product formation, Biotech. Bioeng, pp21, 725.</p><p>J Mendham, Denney RC, Barnes JD, Thomas MJK (2002), Vogel’s textbook of quantitative chemical Analysis (6th ed) pp 508</p><p>Linko M. (1977), an evaluation of enzymatic hydrolysis of cellulosic materials, in Advances in Biochemical Engineering, 5, 39.</p><p>Lubert S; Berg, J M; Tymoczko, J.L., (2002), Biochemistry (5th ed.) San Francisco: W.H. Freeman. ISBN 0-7167-3051-0.</p><p>Smith, A.M (2001), The Biosynthesis of Starch Granules. Biomacromolecules (2nd ed). No 2. Pp 335-41</p><p>Yudkin J, and Hough L, (2002). Sugar Chemical, Biological and Nutritional Aspects of sucrose. Butterworth. ISBN 0-408-71072-2.</p> <br><p></p>