Question

3. There are many symbiotic interactions found in the termite hindgut with representatives from all 3 domains of life. The hindgut protozoa have a number of unique functions in the termite. Discuss it role in fermentation, and how these processes are related to the termite. (5pts)

Answer 1

The protists secrete enzymes that have the ability to convert cellulose in the wood into simple sugars. These simple sugars can be further converted into ethanol by fermentation. The fermentation processes are related to termites.Termites constitutes 95% of the tropical soils and they survive by feeding on wood. Cellulose is the major sugar in the woods which needs to be broken down into simpler molecules called short chain fatty acids in order to be consumed by the termites. The process occurs in the hindgut of the termites and is called fermentation. The termite hindgut consists organism from all 3 domains of life - archae, bacteria and eukarya(protists). The protists in the hindgut carry out the process of fermentation. The following flowchart describes the fermentation process in protists (taken from Nature reviews).

1.The fermentation involes both the temite and the protists activity. The cellulose in the wood is first hydrolyzed in the midgut when mixed with the enzymes such as endogluconases secreted by salivary gland or mid gut of the termites. The partially digested cellulose is further passed to the hindgut. The hindgut contains various ellulolytic protists such as Trichonympha and mixotricha produce cellulases and various glycolytic enzymes such as exoglucanases, exoglucanases, B-glucosidases in the hindgut which are important for the cellulose fermentation. These enzymes act on cellulose and breaks it down into formate.

2.The termite cells use this acid (formate) for nourishment.

3.Formate from the cytoplam can be further fermented to produce CO2, and H2 with the help of hydrogenase enzyme. This occurs in the organelle called hydrogenosome generated by specific anerobic energy carried out by the protists.

4. The prokaryotes associated with protists convert CO2 and H2 into methane and acetate. Termites absorbs acetate as energy source.

5. During this fermentation process ATP is produced and stored as available energy for both the termite and microbe.