Waste yeast conversion in Tonga
Waste yeast from Royal Brewery in Tonga is converted into protein bait used for fruit fly control.
A special project (No 7500) executed by the Queensland Department of Primary Industries under the Australian Centre for International Agriculture Research (ACIAR) collaborated in the development of waste yeast conversion technology, in cooperation with the Regional Fruit Fly Project and the USDA - Commercial Agricultural Development Project.
The conversion process involves, as illustrated below: 1. Concentrating the waste yeast slurry by heating for several hours in an open stirred container to drive off the alcohol and excess water. 2. Treating the concentrated material with a proteolytic enzyme (papain) and holding the concentrate at 65º-70ºC for 24 hours. 3. Adding potassium sorbate as a preservative.
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Steps in waste yeast modification into protein bait (Reproduced from Lloyd and Drew, 1997) |
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Concentration of
waste yeast |
Treatment of
waste yeast with enzyme (papain) |
Extensive field trials were carried out in Tonga to compare effectiveness of locally produced protein bait with Mauri's Pinnacle Protein Insect Lure (MPPIL) imported from Australia, at controlling fruit flies (Bactrocera facialis) on capsicum and chilli. Results show that the local bait is as effective as MPPIL:
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Lure used |
Commodity treated |
Not treated |
Treated |
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97 - 100 % |
< 10 % |
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100 % |
< 5 % |
The commercial product, known as Royal Tongalure, was launched in March 1998 and has been adopted by Tongan farmers. The excess protein is also available as protein additive for stock-feed, especially for pigs. Savings for farmers by using local source of protein are substantial – Tongalure costs TOP 2.00 per litre compared to TOP 30.00 for Mauri Pinnacle Protein Insect Lure imported from Australia.
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Royal Brewery in Tonga is assisting with the transfer of technology on brewery waste yeast modification to Vanuatu Tusker Brewery, its sister brewery. Protein used for fruit fly control has recently been manufactured by the Vanuatu Brewery (September 2002). This protein made from brewery waste yeast is a food attractant for fruit flies. The flies are killed when an insecticide is mixed with the protein. This project was the result of collaborative funding between the Australian Centre for International Agricultural Research (ACIAR), United Nations Development Program (UNDP), AusAID and SPC. The Vanuatu Quarantine and Inspection Service, Vanuatu Brewery and SPC Fruit Fly Management component are involved in the development of the new bait. This protein "Van-lure" will be available by December 2002. Preliminary research is underway to convert waste yeast by Carlton Brewery in Fiji Islands. Breweries in Samoa, Solomon Islands and especially Papua New Guinea have shown interest in adopting the technology.
REFERENCE:
Lloyd,
A., Drew, R.A.I. 1997. Modification
and testing of brewery waste yeast as a protein source for fruit fly bait.
pp. 192-198 in: Allwood, A.J., Drew, R.A.I. 1997. Fruit fly management in
the Pacific. ACIAR Proceedings No 76. 267pp.
Page updated on: 18 October, 2002