Evaluation of Nitrogen Supplements for Bioconversion of Municipal Solid Waste to Lactic Acid
Previous studies conducted by the authors showed that the ingredients of Elliker broth could be used as fermentation adjuncts for the bioconversion of municipal solid waste (MSW) acid hydrolysate to lactic acid. Five kinds of inexpensive organic nitrogen supplements were evaluated for their potential to replace more expensive nitrogen sources derived from tryptone and yeast extract, which are the nitrogenous components of Elliker broth. At a soluble nitrogen concentration of 0. 28%, which is equivalent to that supplied by tryptone and yeast extract, soybean meal and cottonseed meal were the best alternative nitrogen sources and compared favorably to tryptone and yeast extract in terms of lactic acid production. Soybean meal nitrogen of 0. 21% was the minimum nitrogen requirement for maximum production of lactic acid. When soybean meal was used as the nitrogen source, the addition of 1. 91% phosphate as monobasic potassium phosphate significantly improved lactic acid production, but no improvement occurred below 1. 91%. Ascorbic acid and sodium acetate are also components of Elliker broth, and the omission of these from the fermentation substrate did not affect lactic acid production. When 0. 21% soluble soybean meal nitrogen and 0. 4% sodium chloride were supplied to double-sugar MSW (DSMSW) hydrolysate, the amount of carbohydrate used, the percent of carbohydrate converted, the amount of lactic acid produced, and the percent yield after 3 d of fermentation were 78. 3 mg/mL, 91%, 68. 7 mg/mL, and 88%, respectively.
Index EntriesMunicipal solid waste fermentation nitrogen supplements MSW bioconversion lactic acid production
Unable to display preview. Download preview PDF.
- 1.Lipinsky, E. S. and Sinclair, R. G. (1986) Chem. Eng. Prog. 8, 26.Google Scholar
- 2.US Department of Energy (1992) Industrial Innovations for Tomorrow, National Renewable Energy Laboratory, Golden, CO, pp. 1. 2.Google Scholar
- 3.Vickroy, T. B. (1985) Comprehensive Biotechnology, vol. 3, The Practice of Biotechnology: Commodity Products, Moo-Young, M., ed., Pergamon, Oxford, Oxfordshire, UK, pp. 761–776.Google Scholar
- 6.Broder, J. D. and Barrier, J. W. (1993) Municipal Solid Waste and Waste Cellulosic Conversion to Fuels and Chemicals, April 1990—September 1992, Final Report, vol. I: Summary Report, Tennessee Valley Authority, Muscle Shoals, AL.Google Scholar
- 7.Weast, R. C. and Selby, S. M. (1967/68) Handbook of Chemistry and Physics, 48th ed. Chemical Rubber Co., Cleveland, OH, p. B-164.Google Scholar
- 8.Association of Official Analytical Chemists (1984), Official Methods of Analysis, AOAC, Washington, DC, p. 154.Google Scholar
- 9.American Public Health Association (1985) Standard Methods for the Examination of Water and Wastewater, 16th ed., Greenberg, A. E., Trussell, R. R., and Clesceri, L. S., eds., American Public Association, Washington, DC.Google Scholar
- 10.SAS Institute (1992) SAS Language and Procedures: Usage, Version 6, 1st ed., SAS Institute, Inc., Cary, NC.Google Scholar