Hydrolysis of grapefruit peel waste with cellulase and pectinase enzymes.

Approximately 1 million metric tons of grapefruit were processed in the 2003/04 season resulting in 500,000 metric tons of peel waste. Grapefruit peel waste is usually dried, pelletized, and sold as a low-value cattle feed. This study tested different loadings of commercial cellulase and pectinase enzymes and pH levels to hydrolyze grapefruit peel waste to produce sugars. Pectinase and cellulase loadings of 0, 1, 2, 5, and 10mgprotein/g peel dry matter were tested at 45 degrees C. Hydrolyses were supplemented with 2.1mg beta-glucosidase protein/g peel dry matter. Five mg pectinase/g peel dry matter and 2mgcellulase/g peel dry matter were the lowest loadings to yield the most glucose. Optimum pH was 4.8. Cellulose, pectin, and hemicellulose in grapefruit peel waste can be hydrolyzed by pectinase and cellulase enzymes to monomer sugars, which can then be used by microorganisms to produce ethanol and other fermentation products.

[1]  G. Stanley,et al.  Characteristics of cellulase preparations affecting the simultaneous saccharification and fermentation of cellulose to ethanol , 2000, Biotechnology Letters.

[2]  S. Ting,et al.  The Carbohydrates in the Peel of Oranges and Grapefruita , 1961 .

[3]  N. Nishio,et al.  Production of macerating enzymes of mandarin orange peel by fungal cultures , 1979, European journal of applied microbiology and biotechnology.

[4]  L. Ingram,et al.  Effects of environmental conditions on xylose fermentation by recombinant Escherichia coli , 1990, Applied and environmental microbiology.

[5]  Seung-Heon Yoon,et al.  Specificity of yeast (Saccharomyces cerevisiae) in removing carbohydrates by fermentation. , 2003, Carbohydrate research.

[6]  K. Rohmann,et al.  EFFECT OF SEASONAL VARIATION ON ENZYMATIC HYDROLYSIS OF VALENCIA ORANGE PEEL WASTE , 2005 .

[7]  E. Baldwin,et al.  Production of ethanol from enzymatically hydrolyzed orange peel by the yeastSaccharomyces cerevisiae , 1994, Applied biochemistry and biotechnology.

[8]  S. Waffenschmidt,et al.  Assay of reducing sugars in the nanomole range with 2,2'-bicinchoninate. , 1987, Analytical biochemistry.

[9]  C. Whitfield,et al.  The compositional analysis of bacterial extracellular polysaccharides by high-performance anion-exchange chromatography. , 1991, Analytical biochemistry.

[10]  E. Baldwin,et al.  Hydrolysis of orange peel with pectinase and cellulase enzymes , 1992, Biotechnology Letters.

[11]  N. Ben-Shalom.  Hindrance of Hemicellulose and Cellulose Hydrolysis by Pectic Substances , 1986 .

[12]  E. Baldwin,et al.  Fermentation of galacturonic acid and other sugars in orange peel hydrolysates by the ethanologenic strain of Escherichia coli , 1994, Biotechnology Letters.

[13]  T. K. Ghose.  Measurement of cellulase activities , 1987 .

[14]  N. Carpita,et al.  Structural models of primary cell walls in flowering plants: consistency of molecular structure with the physical properties of the walls during growth. , 1993, The Plant journal : for cell and molecular biology.

[15]  L. Ingram,et al.  Parametric studies of ethanol production form xylose and other sugars by recombinant Escherichia coli , 1991, Biotechnology and bioengineering.

[16]  M. Marshall,et al.  A Comparison of Enzymatic and Lime Treatments for Extraction of Alcohol Soluble Solids from Citrus Peel , 1985 .

[17]  T. P. Lyons,et al.  The alcohol textbook , 2003 .

[18]  K. Grohmann,et al.  Fractionation and pretreatment of orange peel by dilute acid hydrolysis , 1995 .