Figure 2. Structure of lactose and its conversion to alcohol by Kluyveromyces marxianus.
α-Lactose HOCH2 O H OH H H OH HO O H H OH HOCH2 O H OH H H OH H
whey and the fermentation process converts the main ingredient (lactose) into alcohol, biomass is produced. The other ingredients of whey will contribute to the BOD/COD of the final effluent from the alcohol plant; and adequate effluent treatment facilities must be provided. One option is to use an anaerobic digestion system. This will convert a portion of the BOD into gas that can be used to fuel the boilers in the distillation plant.
MARKETS FOR ALCOHOL
The alcohol markets in the US and Europe are very different. Because of government intervention in the US, ethanol production has grown from an insignificant amount in 1978 to a record 6.4 billion liters in 1998. In Europe the situation is very different. There has been no such government intervention and an oversupply of alcohol has existed for some time. Until recently a large portion of this alcohol was sold to Russia, but this market has diminished. The low price of oil has helped the majority of alcohol producers to keep production costs down; however as oil prices rise these production costs will also increase.
In the US, ethanol was promoted as a solution for a variety of complex problems. Among them: US dependence on foreign oil supplies, which
was made apparent by two oil crises of the 1970s, and the low gasoline octane ratings caused by reduced use of lead after the approval of the Clean Air Act in 1977. Ethanol production from corn was seen as a way to boost farm incomes caused by the grain surplus in the wake of the Soviet embargo. Also, addition of ethanol to gasoline was seen as a means to reduce air pollution. These provide a ready market for any alcohol produced. Within the EU there has been much discussion about bio-ethanol, but only recently has there been any commitment to bio- fuels. Tax concessions for pilot plants producing bio-fuels have been allowed; and as a consequence new bio-fuel projects have been announced in the Netherlands, Sweden and Spain. France has made the most progress. In 1996 the French approved a draft law that made the use of oxygenated components in fuel mandatory by 2000.
Conclusions
The attachment of a whey alcohol plant to a dairy plant producing the appropriate substrate solves a number of major problems confronting whey producers. Alcohol production provides a guaranteed outlet for the whey that is not subject to the fortunes of pig markets or other elements outside their control. Whey production (or
Table 7. Alcohol plants using whey as a substrate.
Ireland Carbery Milk products, of Ballineen, County Cork, operate an alcohol plant using cheese whey as substrate. This alcohol is used for vodka and cream liqueurs (Murtagh, 1995).
United States A plant to produce industrial alcohol from whey has been installed in California in one of the largest cheddar cheese plants in the world. This plant processes 1,000,000 kg of milk per day into cheese. The whey from the process is converted into permeate and protein by ultrafiltration. The protein is dried and the lactose in the permeate is converted into alcohol. The alcohol is then distilled in a distillation plant capable of processing 200,000 liters of whey per day, producing 1.5 million liters of pure alcohol per year.
New Zealand Whey is the main by-product of the New Zealand dairy industry and is produced in the manufacture of cheese and casein. Anchor Ethanol was the first company in the southern hemisphere to manufacture alcohol from casein whey on a commercial basis. Anchor Ethanol began production at Anchor Products Repora in 1980 and a second plant was commissioned at Anchor Products Tirau the following year. These plants produce a combined total of 10 to 11 million liters of ethanol per year, over half of which is exported. This alcohol is the basis for a range of alcohol beverages. It is also used in the manufacture of solvents, methylated spirits, white vinegar, surgical spirit, food colouring, deodorants, perfumes, aerosols and pharmaceutical products (New Zealand Dairy,1999).
Russia In Russia the range of feedstocks used for alcohol production is very diverse, including grains, fruit, whey, wine and molasses (Berg, 1999).
Whey alcohol - a viable outlet for whey? 73
disposal) does not form a limiting step in cheese or casein production. The whey protein recovered by ultrafiltration is a valuable item, the sale of which contributes to process economics. There is also a universal move towards bio-fuels, therefore the markets for alcohol should be increasingly secure in the future.
References
Berg, C. 1999. World Ethanol Production and Trade to 2000 and Beyond. http://
www.distill.com/berg.
Edelman, E. and S. Grodnick. 1986. The Ideal Cheese Book. http://cbs.infoplease.com/ce5/
CE010398.html.
Eurostat. 1999. Institut National de Statistique, Brussells, Belgium, http://europe.eu.int/en/
comm/eurostat/eurostat.html.
Burgess, K.J. 1980. Uses of waste dairy products. Technology Ireland, June, pp. 43-44.
Murtagh, J.E. 1995. Molasses as a feedstock for alcohol production. In: The Alcohol Textbook (T.P. Lyons, D.R. Kelsall and J.E. Murtagh, eds). Nottingham University Press, Nottingham, UK. pp. 27-34.
New Zealand Dairy.1999. http://www.nzdairy.
c o . n z / p u b l i c / e d u c a t i o n a l / w h e y / e t h a n o l / Ethanol~t.htm.
Nielson, W.K. 1997. Whey processing. Technical Bulletin. APV Ireland Ltd, Dublin.