Name of students: Shwetha Santhosh, Gopika Anil and Ramya Nambiar
College Name: CMR National PU College ITPL
Sample observed: Black bread mould grown on bread kept undisturbed for a week
Site of collection of sample: Bread kept in lab
Rhizopus stolonifer, commonly known as Black bread mould belongs to Class Zygomycetes of Kingdom Fungi.
It is heterotrpohic and dependant on sugar or starch for its source of carbon substances for food. It uses food matter, generally breads or soft fruits as a food source for growth, nutrition and reproduction.
STRUCTURE OF THALLUS: Rhizopus species grow as filamentous, branching hyphae that generally lack cross walls and are coenocytic. Mass of hyphae is called mycelium. They reproduce by forming asexual and sexual spores. In asexual reproduction, the sporangiospores are produced inside a spherical structure, the Sporangium.
Sporangiophores arise among distinctive, root-like rhizoids. In sexual reproduction, a dark zygospore is produced at the point where two compatible mycelia fuse. Upon germination, a zygospore produces colonies of mycelium that are genetically different from either parent.
R. stolonifer is an agent of plant disease; it breaks down organic matter through decomposition. When kept in a moist environment, such as a piece of bread, the parasite can quickly spread within a few days. Its spores are commonly found in the air. The spores grow most rapidly at temperatures between 15°C and 30°C where they are able to germinate to their full potential.
USES : Rhizopus stolonifer is important economically as an agent of post-harvest storage decay. R. stolonifer and other species of Rhizopus also produce Ethylalcohol which is the most important fermentation product. Rhizopus stolonifer is also used commercially to manufacture fumaricacid and lactic acid of high purity. The presence of zinc reduces the amount of fumaric acid produced by the fungus.