Abstract:
Although cassava is an important food in the tropics, it has two major deficiencies which are carried over into those foods made from it: Its content of toxic cyanogenic glucosides and its low content of protein and amino acids. Garri, a fermented cassava food, has previously been ameliorated using organisms which simultaneously secrete linamarase (to reduce the residual cyanise in the food), amylase (to contribute to the groth of fermenting organisms and increase the flavour) and lysine (to improve the amino-acid content of the food). Some of the organisms fermenting cassava for garri production produce appreciabe quantities of linamarase and amylase, but they are low in lysine production. It was therefore decided to improve these organisms by transforming sthem with a synthetic lysine gene coding for an 8-lysine peptide cloned in pBluescript II SK phagemid vector under the control of lae promoter. The synthetic lysine polypeptide gene was successfully introduced into Escherichia coli DH5x and several strains of Lactobacillus spp. and Saccharomyees spp. There was a dramatic increase in lysine secretion in the organisms, ranging from about 2.5 to sixfold, following transformation with the synthetic gene.
