Pilot-scale hydroxylation of FR901459, an immunosuppressive cyclosporine derivative, was performed using resting cells of a Gram-positive bacteria Lentzea sp. 7887 (as whole-cell biocatalysts) and soybean flour as a substrate dispersant. Through biocatalysis, FR901459 was hydroxylated at position 9, producing AS1837812, an important intermediate in the production of drug candidates against hepatitis C. Since FR901459 is insoluble in water, the conversion ratio ([moles of AS1837812 produced/moles of FR901459 added] x 100) of the biocatalysis decreased under conditions with substrate concentrations higher than 0.615 mM. To increase the concentration of FR901459 for biocatalysis, we screened various materials to effectively disperse FR901459 in the biocatalysis mixture and found that soybean flour was the best substrate dispersant. The addition of soybean flour to the biocatalysis mixture increased the FR901459 concentration in a 3-L reactor up to 3-fold (1.85 mM). Thus, we successfully established a pilot-scale (1-m(3)) biocatalysis with a 2-fold higher concentration (1.23 mM) of FR901459 using soybean flour as the substrate dispersant and obtained 419 g of AS1837812 at a conversion ratio of 34.5% in a 28-h batch reaction. Soybean flour can be used as a substrate dispersant for various industrial biocatalysis processes because of its low cost, high availability, and low environmental impact. (C) 2016, The Society for Biotechnology, Japan. All rights reserved.