Культивирование дрожжей на гидролизатах кофейного шлама с целью получения кормовой добавки
2009
Bashashkina, E.V., The D.I. Mendeleev University of Chemical Technology of Russia (UCTR)
Total output of instant coffee in Russia is 130 000 kg per year on average. Only 330-370 kg of the powder but more than 500 kg of wastes are obtained at processing of 1 000 kg of coffee beans. The main byproduct of coffee extraction is a coffee sludge (CS), which contains 50-55% of cellulose, 12.5-13.0% of crude protein, 13.5-15.1% of total fat and 1.5% of extractable carbohydrates. Microorganisms which would be resistant to the toxic components of CS and be able to reclaim the recycle CS hydrolyzates at deep heterophase cultivation were selected. The yeast Saccharomyces cerevisiae race II (YS) were chosen as the most appropriate biological destructors. During the CS preprocessing by acid hydrolysis it was found that for the subsequent cultivation of YS the optimum conditions were: pH 1.0; CS concentration of 100 g/l; temperature of 121 deg processing time of 30 min. The accumulation of biomass was 26 g/l, while a content of protein substances in the final product was 25%. A protein feed product was obtained by deep heterophasic cultivation of CSA culture fluid (CF) filtrate of the previous stage was used to prepare a medium for the each subsequent one and the missing number of mineral components were added into the prepared medium. A recycling of CF was done in the amount of 100%, 50% and 20%. One way of intensifying the process was to remove toxic effects of phenolic compounds and their derivatives which accumulated in the recycling of CF and inhibited a YS growth. The maximum biomass accumulation of YS was 30 g/l and the content of protein was 35.5%, when adding polyvinylpyrrolidone at a concentration of 2 g/l. Adding the substance to the filtrate of CF allowed a recycling from 20 to 70% during 5 next passages without reducing a YS growth.
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