Secretion of lysine in a broth medium by lactic bacteria and yeasts associated with garri production using a synthetic gene

Although cassava is an important food in the tropics, it has two major defi ciencies which are carried over into those foods made from it: its content of toxic cyanogenic glucosides and its low content of protein and amino aci ds. Garri, a fermented cassava food, has previously been ameliorated using organisms which simultaneously secrete linamarase (to reduce the residual c yanide in the food), amylase (to contribute to the growth of fermenting org anisms and increase the flavour) and lysine (to improve the amino-acid cont ent of the food). Some of the organisms fermenting cassava for garri produc tion produce appreciable quantities of linamarase and amylase, but they are low in lysine production. It was therefore decided to improve these organi sms by transforming them with a synthetic lysine gene coding for an 8-lysin e peptide cloned in pBluescript II SK phagemid vector under the control of lac promoter. The synthetic lysine polypeptide gene was successfully introd uced into Escherichia coli DH5 alpha and several strains of Lactobacillus s pp. and Saccharomyces spp. There was a dramatic increase in lysine secretio n in the organisms, ranging from about 2.5 to sixfold, following transforma tion with the synthetic gene.