Cell wall for higher growth rates in diatoms. In brown algae, phlorotannins may be a constituent of the cell walls. The group Oomycetes, also known as water molds, are saprotrophic plant pathogens like fungi. Until recently they were widely believed to be fungi, but structural and molecular evidence has led to their reclassification as heterokonts, related to autotrophic brown algae and diatoms. Unlike fungi, oomycetes typically possess cell walls of cellulose and glucans rather than chitin, although some genera (such as "Achlya" and "Saprolegnia") do have chitin in their walls. The fraction of cellulose in the walls is no more than 4
Glucose oxidase niger". Glucose oxidase is synthesized in several species of fungi and insects where it is used to produce hydrogen peroxide which in turn kills bacteria. Notatin, extracted from antibacterial cultures of "Penicillium notatum", was originally named Penicillin A, but was renamed to avoid confusion with penicillin. Notatin was shown to be identical to Penicillin B and glucose oxidase, enzymes extracted from other molds besides "P. notatum"; it is now generally known as glucose oxidase. Early experiments showed that notatin exhibits "in vitro" antibacterial activity (in the presence of glucose) due to hydrogen peroxide formation. "In vivo" tests showed that notatin