bile juice does not contain any digestive enzymes , yet it is essential for digestion , why so ?

Fats are present in the form of large globules in intestine which makes it difficult for enzymes to act on them. Bile salts present in bile juice break down fats into smaller globules, (i.e. emulsifies fats) which increases the efficiency of enzyme action. In addition, bile juice also makes the acidic food coming from the stomach alkaline, so that pancreatic enzymes can act on them.