The production of surfactin by Bacillus subtilis grown on peat hydrolysate

Summary Horticultural grade sphagnum peat was subjected to acid hydrolysis under various conditions. The hydrolysis was accomplished with concentrations of sulphuric acid between 0.5 and 2% for either 1 or 2 h at 124°C. Six monosaccharides in the hydrolysate were identified by HPLC analysis. A maximum sugar concentration of 7.7g/l was obtained with glucose accounting for 46% of the total.Bacillus subtilis was able to fully utilize all six sugars when the hydrolysate was supplemented with sufficient diammonium phosphate. The production of surfactin seemed to depend on the carbon-nitrogens balance and was inversely correlated to biomass production. With the selection of the proper hydrolysis conditions and nutrient levels the quantity of surfactin produced was as high as with a conventional glucose and mineral salts medium. The surfactin could be used in a peat dewatering process or sold as a co-product from a peat production facility.