TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: The contacting the culture with the production medium produces broth that contains sophorolipid produced by sophorolipid producer. The contacting the culture with the production medium promotes sophorolipid production without significantly affecting cellulase production. The production medium contains carbon substrates. The carbon substrates are provided at intermittent time intervals. The carbon substrates are provided continuously. The carbon substrate is glycerol, glucose, galactose, mannose, xylose, arabinose, lactose, sucrose, fructose, sorbose, maltose, cellobiose, amylase, amylopectin, dextrin, starch, glycogen, cellulose, polysaccharide, yeast extract, peptone, tryptone, amino acid, peptide, protein, milk, fatty acid, glyceride, hydrocarbon, lipidic oil, vegetable oil, rapeseed oil, palm oil, oleic acid, linoleic acid, palmitic acid, lauric acid, fat, alcohol, aldehyde, ester, and ether amide. The production medium is to promote the production of sophorolipids without significantly affecting the production of cellulase. The production medium lacks substrate essential for cell growth. The production medium is free of a nitrogen source. The culture is a non-growing culture. The ratio of sophorolipid producer and cellulase producer is 10:1-1:25, preferably 5:1-1:10, more preferably 1:1-1:4. The method further involves growing sophorolipid producer separate from the cellulase producer, mixing the sophorolipid producer and the cellulase producer to produce the culture, and subsequently contacting the culture with the production medium. The method for producing cellulase, involves providing sophorolipid producer in a first container, providing substrate supported on a production medium to the first container and allowing the substrate to be consumed by sophorolipid producer to produce a broth, providing cellulase producer in a second container, providing the broth from the first container to the second container to produce a culture and allowing the culture to produce cellulase. The broth from the first container to the second container further induces the cellulase producer to produce cellulase. The cells of sophorolipid producer in the broth from the first container are removed before the broth is provided to the second container. The removed cells of sophorolipid producer are recycled back to the first container. The cells of sophorolipid producer are rendered inactive in the broth before the broth is provided to the second container. The method for producing cellulase is a continuous process or batch process. The ratio of sophorolipid producer and cellulase producer in the culture formed in the second container is 0:1-10:1. The method for producing cellulase, involves providing sophorolipid producer in a first container, providing substrate supported on a production medium to the first container and allowing the substrate to be consumed by sophorolipid producer to produce a broth, providing cellulase producer in a second container, providing the broth from the first container and the cellulase producer from the second container to a third container to produce a culture and allowing the culture to produce cellulase. EXAMPLE - No suitable example given.