The wastes of vineyard and olive pruning and olive pulp are abundant in Syria.  Therefore, these wastes were used as raw materials for compost production. The effect of microorganism (yeast) on fermentation process under aerobic and anaerobic condition was studied. The Chemical characteristics of the resulting compost were measured.

The results showed that treatment of the wastes with yeast during fermentation process recorded superiority in the chemical and physical properties of the compost as compared to those without yeast addition. This may indicate the role played by yeast in stimulating the other microorganisms which are responsible for decomposition of wastes. The chemical properties of the compost produced by fermentation of pruning wastes treated with yeast were much better than the other treatments.