ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary A process for the treatment of animal wastes and the production of protein is under development at the University of Queensland. Animal wastes are fermented to produce organic acids which are then utilised by a pellicle-forming yeast, Candida ingens. This is harvested by skimming. The process removes carbon and minerals, particularly calcium and phosphorus, from the medium and Salmonella and Escherichia coli in the wastes are killed. The dry matter yield of C. ingens and its utilisation of volatile fatty acids (VFA) and oxygen were studied in order to improve the understanding of the process. When C. ingens was grown on a synthetic medium containing seven VFA and salts there was a significant increase in yield when the medium was reduced with sodium sulphide or cysteine hydrochloride. The VFA were utilised continuously over 24 h. After inoculation there was a shorter lag phase for the straight chain acids than for propionic and the branched chain acids, isobutyric, and isovaleric, but all acids showed a similar rate of utilisation of carbon during the period of most rapid utilisation. Candida ingens is an aerobe which, when growing as a pellicle, requires a reduced medium analogous to that used by anaerobes. It was concluded that pellicle growth on a medium containing several VFA takes place by utilising oxygen from the gaseous phase above, while all other nutrients are obtained from the reduced liquid phase below.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00500833
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