Abstract
The cultivation of Euglena gracilis on molasses (40g/liter) and ammonium phosphate, monobasic (5.5g/liter) with initial pH 3.5-5.5 gave a satisfactory cell yield and maximum content of cellular protein. The amino acid score of the cell proteins was 89-91 indicating that the Euglena grown on molasses has excellent nutritive value.
The in vitro digestibility of Euglena gracilis grown on molasses was studied by incubating Euglena with trypsin or pepsin. Euglena protein showed good digestibility with each protease: 84.6% by trypsin and 82.8% by pepsin. Rat feeding test was performed with Euglena gracilis grown on molasses to determine the nutritive values of the protein. The nutritive values of Euglena protein were as follows: protein efficiency ratio, 3.28; net protein ratio, 4.50; true digestibility, 93.2%; biological value, 80.2 and net protein utilization, 74.7. These values show that the Euglena protein is highly nutritive and similar to that of the Euglena grown on glucose-glutamate. Consequently, molasses are efficient as a carbon source for production of Euglena protein.
