https://academic.oup.com/ajcn/article/90/3/728S/4597145
The author is an employee of Ajinomoto Co, Inc., the same company that the author of the New Yorker article visited.
Abstract:
In 1907 Kikunae Ikeda, a professor at the Tokyo Imperial University, began his research to identify the umami component in kelp. Within a year, he had succeeded in isolating, purifying, and identifying the principal component of umami and quickly obtained a production patent. In 1909 Saburosuke Suzuki, an entrepreneur, and Ikeda began the industrial production of monosodium L-glutamate (MSG). The first industrial production process was an extraction method in which vegetable proteins were treated with hydrochloric acid to disrupt peptide bonds. L-Glutamic acid hydrochloride was then isolated from this material and purified as MSG. Initial production of MSG was limited because of the technical drawbacks of this method. Better methods did not emerge until the 1950s. One of these was direct chemical synthesis, which was used from 1962 to 1973. In this procedure, acrylonitrile was the starting material, and optical resolution of DL-glutamic acid was achieved by preferential crystallization. In 1956 a direct fermentation method to produce glutamate was introduced. The advantages of the fermentation method (eg, reduction of production costs and environmental load) were large enough to cause all glutamate manufacturers to shift to fermentation. Today, total world production of MSG by fermentation is estimated to be 2 million tons/y (2 billion kg/y).