Yeast of the Microscopic World
As a microscopic organism, I consider myself as very popular, yet intriguingly misunderstood among life forms. Yes, I am alive and thrive in almost any kind of environment. Practically, I have been here millions of years. There are thousands of species of my kind, however human has known a few and the most common is baker’s yeast. In this paper I would like to represent all microbial yeasts known to man and I will address my self as the general “YEAST”
I am neither a plant nor an animal. I am a unicellular organism who belongs to the Kingdom Fungi. Fungi comprises a huge and varied group of organisms that have common characteristics with both the lower plants (algae) and lower animals but are not related to each other. They contain true mitochondria and a membrane-enclosed nucleus. They have no chlorophyll and chloroplast. Reproduction is achieved through sexual and asexual means. Most fungi grow as branched tubular systems, or mycelia, whose individual filaments or hyphae are surrounded by rigid cell walls containing chitin, cellulose, or both, and other polysaccharides. All fungi lack photosynthetic ability and therefore require preformed organic compounds.
Prior to the development of fungi in the microscope in the 1600s, the only fungi described were the higher fungi that have large fruiting structures, such as morels, mushrooms, and puffballs. In 1836, the study of fungi was termed mycology (a branch of botany). The different groups of fungi are classified according to their means of sexual reproduction, life cycle exhibited, growth and developmental stages, and means of asexual propagation.
Yes I am a fungus and like all fungi, dark, damp and humid condition allows me to grow faster, while hot and windy conditions kill me instantly. I cannot produce my own food and solely depend on the food available in my environment or host organism.
My capability to produce enzymes that degrade cellulosic materials has gained popularity in many industrial applications. You could have not possibly enjoyed your beer, liquors and wines without me. For many years now, I have been here helping your bakers prepare your bread. And in recent application showed my great potential in the production of alternative energy such as ethanol. My role in the BioFuels production can no longer be discounted.
Apart from my beneficial uses, human and animals consider me a parasite. I have been accused to cause diaper rash and vaginal yeast infection and yes I am guilty of those accusations. In my opinion, my existence served as a warning sign of a more troublesome conditions brought about by neglect in hygiene and diet.
I am more beneficial than a parasite. Helping people makes me happy, however due to my inability to produce my own food I am forced to consume food from my substrate/host either symbiotically or pathogenically. Before we discuss my beneficial capabilities, I would like to give some tips on how to contain me in the event that I become pathogenic. It is not my intention to help you eradicate all yeast; it’s just that I would like to punish my self for causing troubles instead of good deeds, which I really enjoy the most. Most of all I would like you to regards me as mans best friend.
Remember, I told you earlier that I thrive in dark, damp and humid conditions, as these conditions are optimal for me to grow and multiply rapidly. If my presence is not welcome, just make sure to avoid the said conditions. Exposure to light, wind and high temperature also discourages my presence.
In the event that I become persistent and hard to control there are available antibiotics and fungicides that can arrest my presence but I strongly discourage you to use them against me for it may harm you and besides I can easily develop resistance to those substance. Let me share some secrets with you. I hate vinegar, as it is a basic substance it destroys the sugar present in the substrate or host thus interfering with my metabolic process. Diet is also a good way to avoid me. Low fat and sugar diet keeps me away. Stay away from stinky foods like fish, chicken and eggs if don’t want me in your bodies.
Now for my best kept secret. Would you believe that the best way to control me is to use me as a pro-biotic. Many yeast have expressed antagonistic actions against other yeast and is now gaining popularity in the control of pathogenic yeast. The good thing about probiotics is that it allows containment of the pathogenic organism while keeping the beneficial ones alive. Very important to keep in mind to maintain good populations of the beneficial organism in order contain the pathogenic organisms.
Now that I have shared with you some tips to contain the population of the pathogenic yeast, let us know discuss how can I benefit the human race. For ages I have played a critical role in the process of brewing. My ability to ferment sugar and produce alcohol in the process has evolved and opened many more use of yeast in industries, medicine, food processing and alternative fuel production.
In addition to their roles in the decay of plant and animal residues and in food spoilage, these fungi are of great significance to humans in many other ways. Aspergillus fumugatus, a common inhabitant of the heated compost, can cause respiratory disease in humans, and a number of related species may produce aflatoxin, a tumor inducing alkaloid, in poorly stored moldy grain. A. flavus and A. parasiticus produces aflatoxin, B1, B2, G1 and G2, the first mentioned being the most toxic. The disease caused by Aspergillus is termed as aspergillosis characterized by allergy and infection-like symptoms. The potential threat of Aspergillus as biological weapon of mass destruction is still being investigated.
Species of both Penicillium and Aspergillus are used extensively in commercial fermentations. Camembert cheese derives its flavor from Penicillium camemberti, and Roquefort from P. roqueforti. Soy sauce is fermented with Aspergillus oryzae or A. soyae. This class also includes other species that cause disease in humans, animals and plants; for example the fungus Ceratocystis ulmi is responsible for the Dutch Elm disease, other species cause a wilt disease in oaks and still others reduce the quality in number.
Antibiotics were first fist produced using penicillin from P. notatum; the antibiotic activity of this fungus was first described by Alexander Fleming in 1929. Only through a joint effort of British and American scientists during the World War II, however was the industrial-scale production achieved, by using a better strains of P. chrysogenum. A huge antibiotic industry has since developed. . Various microfungi are used to produced a number of organic acids—gluconic, itaconic and citric acids, for example—and in other chemical processes. Citric acid fermentation yields about 99,000 each year. Penicillium’s uses do not extend to cheese and to antibiotics alone but also in agriculture—serves as soil bioinoculant. Ochratoxin is produced by P. viridicatum and P. verrucosum.