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Citrus-Based Biorefinery - Opportunities and Challenges -

Citrus-Based Biorefinery - Opportunities and Challenges -. www.ars.usda.gov. www.praj.net. Patrick L. Mills Dept of Chemical & Natural Gas Engineering Texas A&M University-Kingsville Kingsville, TX 78363 Patrick.Mills@tamuk.edu. CREL Annual Meeting – Washington University in St. Louis

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Citrus-Based Biorefinery - Opportunities and Challenges -

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  1. Citrus-Based Biorefinery - Opportunities and Challenges - www.ars.usda.gov www.praj.net Patrick L. MillsDept of Chemical & Natural Gas Engineering Texas A&M University-Kingsville Kingsville, TX 78363Patrick.Mills@tamuk.edu CREL Annual Meeting – Washington University in St. Louis Energy: From Molecular Transformations to Systems October 25, 2006

  2. The New Departmental Plan

  3. Starting References 1. B. Kamm, P. R. Gruber, & M. Kamm (editors), Biorefineries – Industrial Processes & Products: Status Quo & Future Directions, John Wiley: New York, ISBN 3527310274, 964 pp, April 2006. 2. R. J. Braddock, Handbook of Citrus By-Products & Processing Technology, Wiley-Interscience: New York, ISBN 0471190241, 247 pp, 1999. 3. R. J. Braddock, “Importance of by-products to citrus juice processing,” Fruit Processing, 5, pp 310-313 (2004). 4. Dan A. Kimball, Citrus Processing: A Complete Guide, 2nd Edition, Chapman & Hall Food Science Series, Aspen Publishers, Gaithersburg, MD ISBN 0834212587, 450 pp, 1999. 5. T. R. Graumlich, “Potential fermentation products from citrus processing wastes,” Food Technology, 94-97, Dec 1983. 6. W. Q. Hull, C. W. Lindsay, & W. E. Baier, “Chemicals from oranges,” Ind. Engng. Chem., Vol. 45, No. 5, 876-890, May 1953.

  4. Orange Citrus segment wall zest Mesocarp or pulp Pericarp or rind Nutrient Composition of Citrus By-Products www.infovisual.info • Lipids - oleic, linoleic, linolenic, palmitic, stearic acids; glycerol & physterol • Sugars - glucose, fructose, sucrose, galactose, xylose, rabinose, ….) • Acids - citric, malic, tartaric, benzoic, oxalic, succinic • Insoluble carbohydrates – cellulose, pectin • Flavonoids, peel oil, pigments, vitamins, minerals, … Morphology of Citrus Fruit • 40 to 65 wt % juice • 35 to 60 wt % waste

  5. Total World Annual Citrus Production* 70 to 105 million tons/yr 2000–2003 (avg’d) C. Paradisi USA 21% ROW 31% C. Limon Brazil 24% Med 24% C. Reticulata - Sour orange - Shaddock - Citron - Lime C. Quanantium C. Grandis C. Medica C. Aurantifolia C. Sinensis *USDA/FAS, 2003 Horticultural & Tropical Products Div.,Wash.,DC

  6. Example: Florida Citrus Production* 90 lbs/box Added Value From Juice By-Products MM = 1 x 106 *USDOE, Office of Energy Efficiency & Renewable Energy

  7. Citrus Juice Process & Material Balance Fresh Citrus Fruit 3000 b/hr 123,000 kg/hr 33.4 % 66.6 % Juice extractors Citrus Juice Wet Peel 54,600 kg/hr 82% H2O Oil Mill / Plant Waste Hammermill (Soluble Fraction) Reaction Time Press Liquid 35,600 kg/hr 9o Brix Waste Heat Evap 30,000 kg/hr d-Limonene 140 kg/hr Presses Press Cake 19,000 kg/hr 65% H2O (Insoluble Fraction) Dryer Feed 25,600 kg/hr 61% H2O Molasses 6400 kg/hr 9o Brix Molasses 4400 kg/hr 72o Brix Pellets 11,000 kg/h 10% H2O Dryer 14,500 kg/hr

  8. Process Flow for Citrus By-Products Fresh Citrus Fruit Residue (Ground or Chopped) Dehydrated without pressing Ca(OH)2 added Citrus Seeds Pressure with Added Ca(OH)2 Dried Citrus Pulp with Liquor Pressure Press Liquor Pressed Fresh Pulp Sieved Dehydration Dehydration Citrus Oils Citrus Molasses Dried Citrus Pulp (w/o Molasses) Dried Citrus Meal Addition Citrus Seed Meal Sold as Molasses Dried Citrus Pulp (with Molasses) Pelleted & Added Back to Pulp Bampidis & Robinson, Animal Feed Sci. Tech. 128 (2006)

  9. Distribution of Citrus By-Products Basis: Oranges = 40.8 kg/box; Juice Yield ca. 55%

  10. Distribution of Orange Juice By-Products Basis: 2005 – 2006 USA Production of 695,275 MT Source: www.fas.usda.gov

  11. Pectin & Pectic Acid Pectin Molecule Pectic Acid (D-Polygalacturonic acid)

  12. Opportunity • Significant growth in use of low-methodoxyl (LM) pectin as a • - Thickening or gelling agent • - In formulated food applications (yogurt, milk, desserts, etc...) Needs • Method for extraction & conversion of high-methodoxyl (HM) pectin • from citrus peels with high efficeincy • New enzyme or catalysts for rapid conversion of HM to LM pectin • Efficient methods for purification and formulation Recovery of Pectin from Citrus Peel Background • Pectin (a polysaccharide) - white, spongy inner part of the peel • Significant yield loss & waste generation with conventional hydrolysis

  13. Citrus Peel Waste as a Bio Feedstock • Represents ca. 40 to 50 % of citrus fruit • Dried pellets used as cattle feed supplement • Second to corn as a source of feed nutrients • CaO added - neutralize & de-esterify pectin • Diffusion controlled process w/molasses • COM can exceed cattle feed selling price • Contains soluble & insoluble carbohydrates • (glucose, fructose, sucrose, pectin, cellulose, • hemicelluloses w/ galacturonic acid, glucose, • arabinose, xylose, … as monomeric units)

  14. Composition of Citrus Juice Processing Wastes (Wet vs Dry Material) • Wet Material • Lower sugar content vs dry material • Lower yield of sugars • Lower energy consumption • Hydrolysis of polysaccharides req’d • Dry Material • Higher polysaccharide concentration • Greater potential yield of sugars • Higher energy consumption vs wet • Higher pectin vs wet material

  15. Composition of Alcohol Insoluble Solids (Cell Wall Fraction of Orange Peel)* Raw Materials for EtOH Production Not Useful for EtOH Production • Fructose & glucose present in nearly equimolar amounts • No starch is present, unlike other Ag resids • Some organic acids, e.g., galacturonic acid Grohmann & Bothast, ACS Symp Ser. 566 (1994)

  16. D-Galacturonic Acid Structure - Formed by the hydrolysis of pectin- Can be converted to d-glucose

  17. Conversion of Orange Total Peel Solidsto Monomeric Sugars- Comparison of Various Treatments- C CG P PC PCG PCG Conversion of total peel solids to monomeric sugars by enzymatic and combined acid and enzymatic treatments. Left bar (Unt) of each pair represents a mean of results obtained by enzymatic treatment alone, without acid treatment. The right bar (Tr) of each pair represents the mean of results obtained by sequential acid and enzymatic treatment. The symbols above each pair of bars represent the enzymes (or combination of enzymes) used in the enzymatic part of the treatment (C=cellulase; P=pectinase; b-glucosidase). The last pair of bars, labeled I"PCG, represents results of a treatment with a mixture of pectinase, cellulase and ~-glucosidase in excess. The individual sugars released are marked on the right side of the graph (Ara=arabinose; Fru=fructose; Gal=galactose; Glc=glucose; G.A=galacturonic acid; Xyl=xylose). Grohmann, K.; Cameron, R.G;. Buslig, B.S Bioresource Technology 54 (1995) 129-141

  18. Products from Various Solubilization Methods

  19. Enzymatic Hydrolysis of Orange Peel Enzymatic w/dilute acid pretreatment Enzymatic w/o acid pretreatment Conversion of total peel solids to reducing sugars during enzymatic hydrolysis of untreated orange peel ( ...... ) and peel pretreated with 0-06% sulfuric acid at pH=2.0 at 100, 120 and 140°C for 10 min, respectively. Treatments: a No acid pretreatment;---<> . pH=2-0, 100°C, 10 min; ---o . . . . pH=2.0, 120°C, 10 min; - - - + . . . . pH=2.0, 140°C, 10 min.. Grohmann, K.; Cameron, R.G;. Buslig, B.S Bioresource Technology 54 (1995) 129-141

  20. Effect of Particle Size onEnzymatic Hydrolysis of Cellulose Attrition mill SS beads Glass beads conv. ball milling w/o milling Comparison of shake-flask and attrition methods for enzymatic hydrolysis of Whatman CF-11 cellulose. (  ) Unmilled control, () ball milled, () 60 g of glass beads, ( ) 136 g of stainless-steel beads, all with a shaker speed of 200 opm. () Attrition at 200 rpm. Cellulase complexPP 158: 1 IU/mL and 2% substrate. Neilson M. J., Kelsey, R. G ., and Shafizadhe F (1982). Biotechnology and Bioengineering, Vol. XXIV, pp. 293-304

  21. Opportunity • Develop methods and process with significantly higher • conversion rates and selectivities to monomeric sugars Needs • Novel enzymes, catalysts, and reactor systems • Basic data on the reaction mechanism & kinetic-transport effects • Mathematical models for kinetics, transport, & reactor systems Novel Hydrolysis Schemes of Citrus Peel Background • Peel celluose & hemi-cellulose contain value-added glucose, sucrose,.. • Existing hydrolysis methods are slow (on the order of days) • Lack of basic understanding of hydrolysis kinetic-transport effects

  22. Production of Orange Juice By-Products Basis: 2005 – 2006 USA Production of 695,275 MT Source: www.fas.usda.gov

  23. PdCl2/ CuCl2 + O2 + tert - BuOH tert – BuOOH (aq.) R-Limonene tert-butyl peroxide derivatives Catalytic Oxidation of Limonene w/o LiCl with LiCl PdCl2/ CuCl2 + O2 or HOAc 15 hr, pH = 6 trans-carveol a-terpinyl acetate R-Limonene

  24. b. Wacker with t-BuOH & t-BuOOH Oxdn of Limonene - Product Distribution a. Conventional Wacker

  25. Opportunity • Limited literature exists on application to natural products • Synthesis of new molecules, specialty polymers, & materials Needs • New organometallic catalysts for mono-terpene functionalization • Fundamental studies on kinetics, mechanisms, multifunctional reactors • Novel multiphase microreactor system designs & mini-plants Functionalized Derivatives of D-Limonene Background • Limonene & other mono-terpenes are recovered from citrus peel oil • Derivatives (alcohols, aldehydes, ketones, allylic ethers, carboxylic • acid esters, epoxides…) are useful in pharma, perfumery, flavors

  26. Example of a Flavonoid - Diosmetin • A human CYP1A enzyme activity-inhibiting natural flavonoid. • Diosmetin has antimutagenic and anti-allergic behavior.

  27. Flavones & Flavonoids • Naturally occurring aromatic secondary • plant metabolites • > 4000 have been identified in plants • Positive health benefits • - antioxidants - cardioprotective • - antiviral - anticarcinogenic • - antiallergenic • Amount & type depends on citrus genus • and agricultural growth factors

  28. Opportunity • Develop rxn-sepn methods or processes that convert these • to value-added products (flavors, perfumes, nutraceuticals,..) Needs • New enzymes, catalysts, and/or reaction-sepn processes • Insight and new data on mechanisms & kinetic-transport effects • Mathematical models for the kinetic-transport processes Novel Sepn & Conversion Methods for By-Products Background • By-products (lignin, protein, limonene..) are produced in various • parts of the existing citrus process (hydrolysis, milling, etc.) • Some behave as enzyme inhibitors, microbiocides, contaminants,…

  29. Conclusions • Citrus waste has potential as a biorefinery platform. • Notable differences vs corn & grain-based processes. • Conversion to EtOH represents one useful application. • Specialty products would enhance economic potential. • Various opportunities for novel enzymes, catalysts, • reactors, separations, & derivatives.

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