State two economically important uses of:
(a) heterotrophic bacteria (b) archaebacteria 

Explanation

(a) heterotrophic bacteria :
(i) Bacteria are natural scavengers. They obtain their nutrition by decomposing dead bodies, dead plants and animal excreta.
(ii) These are used in fermentation process for vinegar manufacturing, yogurt making etc.
(iii) Somc bacteria help in retoing of jute and coconut plant fibres.
 (iv) The genus streptomyces has many species used to produce different antibiotics.
(v) Bacteria play important role in different steps of nitrogen cycle.
(b) archaebacteria :
Archaebacteria can live in extreme environments so they are useful in :
(i) Modern biotechnology
(ii) Generation of biogas
(iii) Thermophilic enzyme
(iv) Biosensors
(v) Restriction enzymes