CHEMICAL INDUSTRY PROCESS
MANNITOL
Monica Yulfarida 21030116130166
Zinedin Abdi Zidan 21030116120044
MANNITOL
A. Introduction
Mannitol is classified as a sugar alcohol. It can be derived from a sugar
(mannose) by reduction other sugar alcohols include xylitol and sorbitol. Mannitol
and sorbitol are isomers, the only difference being the orientation of the hydroxyl
group on carbon 2.
B. Raw Materials
Mannitol is the most abundant polyol in nature. It is produced by bacteria,
yeasts, fungi, algae, lichens and many plants (Wisselink et al., 2002). Mannitol is
about half as sweet as sucrose, mostly not metabolized by humans and therefore
considered as a low-calorie sweetener (Soetaert et al., 1999).
Mannitol is commonly produced via the hydrogenation of fructose, which is
formed from either starch or sucrose (common table sugar). Although starch is a
cheaper source than sucrose, the transformation of starch is much more complicated.
Its sweetness is approximately half as compared to sucrose. However, like other sugar
alcohols, mannitol exhibits reduced caloric values compared to that of sucrose,
making it applicable as sweeteners in so-called light foods.
C. Process and Description
Mannitol is produced industrially by high pressure hydrogenation of fructose
and glucose- fructose mixtures in aqueous solution at high temperature (120160 C)
with Raney nickel catalyst. -Fructose gets converted to mannitol and -fructose is
converted to sorbitol where as glucose is exclusively hydrogenated to sorbitol. Due to
poor selectivity of the nickel catalyst, hydrogenation of 50:50 fructose:glucose
mixture results in an approximately 25:75 mixture of mannitol and sorbitol (Saha &
Racine, 2011). Even when pure fructose is catalytically hydrogenated, only about
50% of it is converted into mannitol, whereas the rest is converted into sorbitol.
Chemical hydrogenation process has several limitations, including the need for
highly purified substrates, high reaction temperatures and pressures, costly
purification steps and a poor mannitol yield.
Further research is being conducted, studying ways to engineer even more
efficient mannitol pathways in lactic acid bacteria, as well as the use of other
microorganisms such as yeast and E. coli in mannitol production. When food-grade
strains of any of the aforementioned microorganisms are used, the mannitol and the
organism itself are directly applicable to food products, avoiding the need for careful
separation of microorganism and mannitol crystals.
Several lactic acid bacterial strains are known to produce mannitol. Its
production by food-grade lactic acid bacteria offers important advantages. Firstly,
their products are directly applicable in food products, without any restriction.
Secondly, there is no need for a careful separation of products and microorganisms.
Thirdly, some LABs are claimed as beneficial in the gastrointestinal tract. Mannitol
production by those bacteria may strengthen their health-promoting ability.
D. Block Diagram
Figure 1. Block Diagram of Mannitol
E. Flow Sheet
Figure 2. Flow Sheet of Mannitol Production
F. Specification
Figure 3. Specification of Mannitol
G. Uses of Mannitol
Major applications of mannitol are:
1. Food industry as a food additive. It is used as a sweet-tasting, bodying and
texturing agent.
2. The primary ingredient of mannitol salt agar, a bacterial growth medium, and is
used in others.
3. Increases blood glucose to a lesser extent than sucrose,so is used as a sweetener
for people with diabetes, and in chewing gums.
4. Popularly used as a cutting agent in cocaine.
H. REFERENCES
Saha, B., Racine, F. 2011. Biotechnological production of mannitol and its
applications. Applied microbiology and biotechnology, 89(4), 879-891.
Soetaert, W., Vanhooren, P., Vandamme, E. 1999. Production of mannitol by
fermentation. Methods Biotechnol, 10, 261-275.
Wisselink, H.W., Weusthuis, R.A., Eggink, G., Hugenholtz, J., Grobben, G.J. 2002.
Mannitol production by lactic acid bacteria: a review. International Dairy
Journal, 12(2-3), 151-161.
