Mucor piriformis

Rhizopus-soft rot is a threat in all postharvest situations including storage, marketing, and transport of crops. It causes soft rot of avocados, cassava, crucifers, pulses, yams, and sweet potatoes. This spoilage type is mainly caused by Rhizopus stolonifer and to a lesser extent by R. oryzae, Mucor piriformis, and Gilbertella persicaria (Dijksterhuis and Samson 2006). 

Both pectate-based culture filtrates and ripe strawberries, artificially inoculated with Rhizopus stolonifer, R. sexualis, Mucor piriformis, ox Aureobasidium pullulans, contained erado-poly-D-galacturonase and pectin esterase. Uninfected... 

The stability of pectin-depolymerizing enzymes (poly-D-galacturonases) produced by Mucor piriformis, Rhizopus sexualis, R. stolonifer, Botrytis cinerea, Aureobasidium pullulans, Trichosporon puUulans, and Cryptococcus albidus var. albidus in sulphite liquor was studied in relation to the breakdown of sulphited strawberries. Marked breakdown of fruit occurred only when pectolytic activity could be detected in the liquor for more than two weeks using a viscometric assay. Of the fungi tested, Rhizopus species produced enzymes which were most stable in sulphite liquor. For each of the Mucor and Rhizopus species tested, the stability of poly-D-galacturonases in sulphite liquor was very similar for extracts of infected fruit and culture filtrates. It was suggested that sulphite labile (= acid labile) and sulphite stable (= acid stable) forms of the poly-D-galacturonases are present. 

---