143. Given below are two statements:
Statement I: Fungi are important degraders of polymers and are used in the composting and
biodegradation of toxic organic substances.
Statement II: Fungi are able to selectively excrete toxins present in these polymers.
In the light of the above statements, choose the correct answer from the options given below:
A. Both Statement I and Statement II are true
B. Both Statement I and Statement II are false
C. Statement I is true but Statement II is false
D. Statement I is false but Statement II is true

The Role of Fungi in Degradation and Biodegradation of Organic Substances

Fungi play an essential role in the natural recycling of organic material by breaking down complex compounds into simpler forms that can be utilized by other organisms. Fungi are considered important degraders of polymers, and they play a key role in processes such as composting and the biodegradation of toxic organic substances.

Statement I: Fungi as Degraders of Polymers and Biodegraders of Toxic Substances

Fungi are known for their ability to break down a variety of organic polymers, such as cellulose, lignin, and chitin. This degradation is achieved through the secretion of extracellular enzymes that break down complex polymers into simpler molecules that fungi can absorb and use as nutrients.

In addition to their role in the natural degradation of plant material, fungi are also used in composting processes, where they help to convert organic waste into humus, which is beneficial for soil quality. Fungi are also involved in the biodegradation of toxic organic substances like pesticides, industrial waste, and pollutants by breaking down these harmful compounds into less toxic forms.

Thus, Statement I is correct. Fungi do indeed play a crucial role in degrading polymers and biodegrading toxic organic substances.

Statement II: Fungi Excrete Toxins

While fungi are effective degraders of organic compounds, their role in selectively excreting toxins from these polymers is more controversial. Fungi can produce a variety of secondary metabolites, some of which are toxic (e.g., mycotoxins), and these compounds may be released into the environment. However, this is not a selective process for excreting toxins from polymers that they degrade. Instead, the production of mycotoxins is often a defense mechanism against environmental stress or competition, rather than a targeted action to excrete toxins from the compounds they degrade.

Thus, Statement II is false. Fungi do not selectively excrete toxins from the polymers they degrade. Instead, they may release secondary metabolites, including mycotoxins, as a byproduct of their metabolic processes.

The Correct Answer

Based on the analysis:

Answer: C. Statement I is true but Statement II is false

Conclusion

Fungi are critical players in the degradation of polymers and the biodegradation of toxic substances, contributing to processes such as composting. However, their ability to selectively excrete toxins from the compounds they degrade is not supported by current scientific understanding. While they may produce toxins as part of their metabolic processes, this is not directly related to the degradation of organic polymers.