Shanna Ball
Prof Heather Killen
Bio 205
February 20, 2012
Summary of Random mutants of a Pleurotus ostreatus laccase as new biocatalysts for industrial effluents bioremediation
The focus of this research project is to “select better performing laccase variants of Pleurotus ostreatus POXA1b laccase to develop improved laccase-based biocatalysts”. The mutations are created through directed evolution, whereas one simulates evolution (natural selection) to create the ideal substance not original to nature. (V. Faraco, et al., Wikipedia 3.)
Laccases are oxidase enzymes, meaning that they need oxygen in order to promote a reaction. Laccases contain copper and are found in microorganisms, fungi and plants. ‘Laccases act on phenols’, performing ‘one-electron oxidations’ and are thought to ‘play a role’ in lignin formation ‘by promoting the oxidative coupling of lignols’. This specific type, Pleurotus ostreatus, aids in breaking down lignin. Pleurotus ostreatus is actually a type of edible mushroom (the oyster mushroom) which grows naturally and commercially for purposes such as food, mycoremediation, as well as medicinal. However, for this experiment scientifically evolved forms of this fungal species were created and selected in order to fulfill the specified need for tolerance towards pH and temperature variations. (Wikipedia 1, 2)
There are thousands of mutated forms of “Pleurotus ostreatus POXA1b”. The problem lies in that the original “wild-type” and a number of first generation mutated types cannot stand up to specific environments such as acidic and alkaline pH levels and/or temperature variants. Thus, it can be difficult to utilize them for varying conditions of bioremediation. However, this current research allows us to hypothesize that it is possible to mutate the Pleurotus ostreatus so as to allow for beneficial bioremediation. (V. Faraco, et al)
Without getting too in-depth on the process, the outcome of the reactions of laccases on specific compounds and their substrates is the binding of oxygen molecules which then reduce to water molecules. This is highly beneficial in pulp bleaching within the paper industry, textile dye decolourization, and the detoxification of environmental pollutants and organic synthesis. (V. Faraco, et al)
The study began with a first generation mutation to the original wild-type version. There were 2300 evolved mutant variants created within this first generation. An error occurred, creating an additional 1100 clones. Of these 1100 error clones, one mutated enzyme was selected as a template in creating a second generation mutation process. Of the overall thousands of mutant enzymes created, a handful demonstrated properties equivalent to fulfill the original hypothesis. (V. Faraco, et al)
Due to the conditions of the outcome, the new laccase mutants formulated show increased versatility and durability as biocatalyst over their original wild-type enzyme and first generation mutations. They show good potential for bioremediation within such areas as textile wastewaters, chemical-plant wastewater, xenobiotic transformation, organic synthesis and enzymatic polymerizations. The conclusion to this research is highly beneficial and positive in the decomposition (bioremediation) of industrial waste utilizing the formulated mutated Pleurotus ostreatus. (V. Faraco, et al)
Works Cited
V. Faraco, et al. "Random Mutants Of A Pleurotus Ostreatus Laccase As New Biocatalysts For Industrial Effluents Bioremediation." Journal Of Applied Microbiology 108.3 (2010): 998-1006. GreenFILE. Academic Search Complete. EBSCO. Web. 20 Feb. 2012.
Wikipedia. 20 Feb 2012
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