1. Introduction
Lactic acid is used as a monomer in the preparation of polylactic acid, a type of environment-friendly alternative to petr
ochemicals plastics 1-3.
Generally, the starchy materials like corn, rice, wheat, barley and so on, are the preferred carbon sources used in lactic acid production at present 4, 5 .
However, in some countries, grain is not advocated to be used as industrial lactic acid because of its high price and short supply. Non-grain raw material