Why Can the Japanese Digest Nori while North Americans Can’t? Horizontal Gene Transfer and Pasteurization

Porphyran is a complex sulfated carbohdrate found in abundance in seaweed species, such as those belonging to the genus Porphyra from which the sushi ingredient nori is made. The backbone of the molecule porphyran can be hydrolyzed by a group of enzymes called porphyranases . In nature, porphyranase-coding genes are found in the genomes of a group of Gram-negative anaerobic bacteria called…