Presentation on theme: "9/21/2010 1 BIOREMEDIATION AND BIOMASS UTILIZATION Iman Rusmana Department of Biology Bogor Agricultural University Bioremediation Bioremediation is defined."— Presentation transcript:
9/21/ BIOREMEDIATION AND BIOMASS UTILIZATION Iman Rusmana Department of Biology Bogor Agricultural University Bioremediation Bioremediation is defined as the process whereby organic wastes are biologically degraded under controlled conditions to an innocuous state, or to levels below concentration limits established by regulatory authorities. Bioremediation uses naturally occurring bacteria and fungi or plants to degrade or detoxify substances hazardous to human health and/or the environment. The microorganisms may be indigenous to a contaminated area and stimulated in activity (biostimulation) or they may be isolated from elsewhere and brought to the contaminated site (bioaugmentation).
9/21/ Problems with bioremediation Work in vitro, may not work in large scale. Work well in the laboratory with simulation, may not work in the field. Engineering approach is needed. Alternatively, select adapted species on site (indigenous species) to remediate similar damage. Most sites are historically contaminated, as a results of the production, transport, storage or dumping of waste. They have different characteristics and requirements. Those chemicals are persistent or recalcitrant to microbial breakdown. Use of bacteria in bioremediation Greatly affected by unstable climatic and environmental factors from moisture to temperature. For examples, pH in soil is slightly acidic; petroleum hydrocarbon degrading bacteria do not work well < 10 C. These microbes are usually thermophilic anaerobic. Fertilizers are needed. Seeding or bioaugmentation could be useful too. They contain monooxygenases and dehydrogenases to break down organic matters including most toxic substances.
3 9/21/2010 Biomass Utilization Renewable Bioresource Feedstock Plants – crops – trees – algae Animals, fish Microorganisms Organic residues – municipal – industrial – agricultural – forestry –aquaculture Industrial Bioproducts Bioenergy and Biofuels Manufactured products: – biochemicals – biosolvents – bioplastics – ‘smart’ biomaterials – biolubricants – biosurfactants – bioadhesives – biocatalysts – biosensors Bioprocess Technology Biocatalysis (Enzymes) Fermentation (Microorganisms) Physical – Chemical Process Technology Extraction Pyrolysis Gasification The diffusion of biotechnology and green chemistry across the economy Additional ‘Sectors’ Informatics Genomics Nanotechnology Security Services Health and Medicine Biopharmaceuticals Vaccines Diagnostic kits Artificial organs Gene therapies First Wave Agriculture and Food Disease and drought resistant crops Functional foods Nutraceuticals Biopesticides Second Wave Industrial Bioproducts Biofuels and bioenergy Manufactured products Biochemicals Bioplastics Biolubricants Biocatalysts Biosensors Third Wave
4 9/21/2010 Advantages of Biomass Utilization feedstock waste Energy Fossil Carbon Economy - carbon is used and discarded Fossil Carbon Carbon Cycle in Nature Carbon Cycle in Industry Bioproducts Economy - carbon is recycled Carbon Cycle in Industry Renewable Carbon Cycle in Nature Petroleum Mat Rain coat Sandals Shoes Plastics, Fabrics, Synthetic rubber, etc. Hut Umbrella Rope Fertilizer Chemicals Waste is a feedstock opportunity Growth from increasing value added （１９８９～ 2010 ） Gas oven Cars Electric oven ＋ Waste Oven ENERGY Compost CO 2 Sandals Shoes Mat Rope Biomass Utilization Rain hut Rain coat Rice straw Waste is a disposal problem Growth from increasing production volume （ 1603 ～ 1867 ） Future （ 2010 ～ 2020 ） Biomass Refinary Bioplastics Biogass Alcohol Recycle composting
9/21/ Why ＢＩＯＭＡＳＳ ? 1. To substitute or complement drying up petroleum. 2. To reduce the amount of CO 2 emission. 3. To decrease (urban/agricultural /forestry) organic wastes. 4. To re-activate rural life and economy. Special waste bioprocesing -- Degradation of oil in spills -- Degradation of xenobiotics (chlorinated insecticides, herbicides and fungicides) -- Degradation of polymers (plastics) -- Transformation of toxic metal species into less or non-toxic forms.
9/21/ Pseudomonas Genetically engineered bacteria (Pseudomonas) with plasmid producing enzymes to degrade octane and many different organic compounds from crude oil. However, crude oil contains thousands of chemicals which could not have one microbe to degrade them all. Controversial as GE materials involved. Degradable organic compounds in the environment 1) Biodegradable: undergoes a biological transformation. Complete degradation results in CO 2 and some inorganic compounds 2) Persistent: do not biodegrade in certain environments 3) Recalcitrant: resist biodegradation in most environments Not always beneficial process: 1) non toxic compound toxic metabolite, 2) toxic chemical more toxic chemical (mercury waste transformed into very toxic methyl mercury compounds).
9/21/ Microbes have the ability to consume natural or synthetic organic substances as nutrient and energy sources Pseudomonas group – digest more than 100 organic compounds Microbes have an extensive set of enzymes that can serve as a raw material for further mutagenesis Modified enzymes = Digesting new substrates, working in altered environment or having improved kinetics “Catabolic plasmids” of Pseudomonas 1) Encode enzymes for waste-degradation pathway 2) Could be transferred between species 3) Transfer across the community increases in response to novel nutrient use, or exposure to a potentially toxic compound. Enzymes of catabolic plasmids able to degrade : octane, naphthalene, toluene, benzene, pesticides, herbicides...
9/21/2010 Examples of naturally occurring “catabolic plasmids” capable to interspecies transfer Compound Biphenyl Plasmid pBS241 Size 195 kb Bacterium P. putida Camphor pPG1(CAM) Near 500 kb Pseudomonas sp. Octane Chlorobiphenyl OCT pSS50 Near 500 kb 53.2 kb P. oleovorans Alcaligenes spp. From Microbial Ecology, 19:1-20, 1990 Ananda Chakrabarty’s “Super-Pseudomonas” 1974 Chakrabarty created super-Pseudomonas degrading oil in spills Plasmids CAM (camphor degradation), OCT (octane degradation), NAH (naphtaline degradation) and XYL (Xylol degradation) were combined in the same cell 8
9/21/2010 Creation of Super-Pseudomonas XYLCAMNAH Conjugation XYL NAH CAM/OCT XYLNAH OCT Conjugation CAM/OCT Conjugation CAM (camphor degradation), OCT (octane degradation), NAH (naphtaline degradation) XYL (Xylol degradation) Pseudomonas putida mt-2 (pWWO) very good bacteria capable of decontaminating organic substances including solvents, such as toluene, one of the components of gasoline. very common in soil and plant rhizosphere It promotes plant growth, is a biocontrol agent for plant pathogens 9
catabolic plasmid 10 H OH Ortho-cleavage Benzene Ortho-cleavage pathway (chromosomal) Meta-cleavage pathway (TOL catabolic plasmid), activated when Acetyl CoA Succinate chromosomal pathway overloaded Acetaldehyde Pyruvate Degradation of benzene by pseudomonads (cited in Galzer and Nikaido, Microbial Biotechnology, Freeman and Company, NY) Different benzene derivatives induce different degradative pathways; TOL cleavage supply P. putida with energy 9/21/2010 1,2-dihydro- TOL 1,2-dihydroxybenzene Meta-cleavage H Catechol OH 2,4,5-trichlorophenoxyacetic acid ( 2,4,5-T) Burkholderia cepacia 2,4,5-trichlorophenoxyacetic acid Succinate + Acetate Dioxygenase WIDELY USED HERBICIDE Cl Makes molecule difficult to degrade Burkholderia cepacia
9/21/2010 Most biodegradation-performing bacteria are mesophilic (20-40 C is their growth optimum) Rivers or soils that need to be cleaned are at 0-20 C are difficult to clean !!! SAL TOL Psychrophilic Strain (cold-liking) Mesophilic strain Conjugation SAL TOL Result: Psychrophilic strain degrading both Salicilate and Toluene Difficulties with releasing biodegrading “lab” microbes into the environment Gadd, G.M., 1993, Trends in Biotechnology, v. 11, p
12 9/21/2010 Plant carbohydrates is a valuable material for industry STARCH cellulose Starch – edible for humans. Cellulose – non-edible for humans Cellulose microfibrils
9/21/2010 Cellulose Lignin Amorphous Region Pretreatment gives enzyme accessible substrate Pretreatment Crystalline Region Hemicellulose STARCH 13
9/21/ Cellulose Starch Amylose Amylopectin (100 – glucose monomeres) ( – glucose monomeres) corn starch from waxy maize contains only 2% amylose but that from amylomaize is about 80% amylose.
9/21/2010 Annual world production of commercial starches in millions of metric tons Botanical Source Maize Potato Tapioca & others Wheat Total / Extractives Ash Hemicellulose (need special yeast to convert to ethanol) Chapple, 2006; Ladisch, Components of plant cell walls Cellulose Fermentable sugars obtained from cellulose in 1819 Lignin
16 9/21/2010 Uses of non-usable banana starch glucose Straw degradation in flask ControlInoculated day 0day 4 day 8 day 10
9/21/ Major Microorganisms in the consortium GlucoAmylase is able to digest branching points Is derived from Aspergillus niger; A. awamori Alpha-Amylase genes from B.amyloliquefaciems; B.Stearothermophilus (both expressed in B. subtilis) Glucose sirup
9/21/2010 Yeast Metabolism: pentose fermentation Phosphoenolpyruvate Pyruvate Acetaldehyde Ethanol TCA Cycle Xylose Xylitol Xylulose Xylulose-5-P NADH NAD+ Glucose Glucose-6-P Fructose-6-P Glyceraldehyde-3-P NAD+ NADH 3-Phosphoglycerate NAD(P)H NAD(P)+ NAD+ NADH PPP Ho et al From Xylan: Total: 30 to 35 gal / ton 80 to 85 gal / ton. Corresponds to about 250,000 tons /yr for 20 million gal per year plant Requires engineered yeast, pretreatment cellulase enzymes 18 Yields of Ethanol from Corn Stover (Cellulose Ethanol) From Cellulose: 50 to 55 gal / ton
9/21/2010 Ethanol is renewable energy source (better than oil) Ethanol vehicles produce : 35% less CO 42% less NOx 43% less NMHc (nonmethane hydrocarbon) 39% less PM (particulate matter) 79% less CO2 over life cycle Previous pictures were about starch; It will be nice to transform cellulose (woods) Hydrolysed Hemicellulose and Lignin Lignin into ethanol too… Glucose Ethanol 19
9/21/2010 Cellulose waste Lignin Complex aromatic (organic) polymer -- no simple repeat unit -- hydrophobic-repels water -- acts as an adhesive Cellulose itself Cristalline; amorhous Hemi-Cellulose Combinations of 5 or 6 sugars; Side groups (branching) Amorphous in cell wall -- stiffens wood Hemicellulose (a mix of many monomeres) Usually, all of the pentoses are present. The pentoses are also present in rings that can be 5-membered or 6-membered. Xylose is always the sugar present in the largest amount. 20
9/21/ Problems with commercial glucose production from cellulose waste 1. typical waste cellulose material contains less than half cellulose (lignin and pentosans are non-degradable contaminants). 2. A combination of enzymes is needed to solubilize and degrade cellulose waste. 3. Natural enzymes are comparatively unstable or have low activity against complex of the lignin and cellulose. Enzymes are subject to both substrate and product inhibition. cost of cellulose glucose conversion is excessive Strach is more expensive to produce than cellulose, but starch glucose is much cheaper Most pure cellulose sources (most easily transformed to glucose) are most expensive ones
9/21/2010 Cellulose (hydrolysed by cellulases) Cellulases Cellulose is associated with lignin and pentosans, so as to resist biodegradation; dead trees take several years to decay even in tropical rainforests. Cellulases cellobiohydrolase (CBH) hydrolyse the cellulose chain from one end endoglucanase (EG) Cut randomly Inside the cellulose chain. hydrolyse cellulose cooperatively, i.e. they act in synergy. endoglucanase (EG ) 22
9/21/ first, hemicellulases may digest hemicellulose (and open up wood for bleaching, cellulose to be extracted etc…) Enzyme complex: arabinosidase, mannanase, mannosidase and xylanase. Enzyme source: Fermentation of a nonpathogenic strain of Aspergillus niger. Xylose is produced from hemicellulose in large amounts!!! Xylose is major component of waste. Would be great to transform it to ethanol somehow !!!
9/21/ Ideal biocatalyst microorganism: -- Creates ethanol from glucose (from cellulose) -- Creates ethanol from xylose (from hemicellulose) -- Capable to high-yield ethanol production -- Growth in industrial settings No “ideal bug” exists yet Zymomonas mobilis Advantages: – Natural fermentative microorganism – Near theoretical ethanol yield from glucose (92%-94% versus 88%-90% for yeast) – Shorter fermentation time (300%-400% faster than yeast) – No oxygen requirement – Tolerant to inhibitors in hydrolysates – High ethanol tolerance – Fermentation at low pH – Grows at high sugar concentrations – High specific productivity Limitations: – Narrow substrate utilization range (only pure glucose)
9/21/ a strain of Zymomonas mobilis that produces ethanol from both xylose and glucose was created DOE is assisting Arkenol Inc. (California) in building a new biomass-to-ethanol plant that will provide 8 million gallons per year of ethanol from rice straw using the Zymomonas mobilis process. This project provides an alternative to rice straw burning, which is being phased out in California for environmental reasons. Similar result achieved with genome-integrated copies of XYL-ARA genes (greater strain stability)
26 of p-coumaril alcoholssoftwoods 9/21/2010 The problem of non-degradable lignin remains: Lignin Hardwoods softwoods Amorphous co-polymer
hydrocracking Hydro deoxygenation Hydrogeno lysis Hydrogeno lysis 9/21/2010 Lignin derivatives used as fuel additives (to increase octan number) (Chemical process) (In stirring autoclave) Lignin System of Biomass Utilization 27 Fallow rice pad Ethanol Station Public Education Town Office Volunteer Center Ethanol car Ethanol truck Ranch Ｓｔｒａｗ／Ｈｕｓｋ Rice production Non-eatable parts Fields Horticulture Ｉｎｄｕｓｔｒｉａｌ ｃｒｏｐｓ Forest Wood waste Others Ｗａｓｔｅｓ Agricultural Products Distribution Other usage of Ethanol Ethanol bus Coperation Compost Center Waste Treatment Local Economy Sightseeing Hotel Restrants Brewery Center Local Government Local Education High School
Biodiesel Ethanol Blend Plant Cellulose CO 2 Algae CO 2 E. coli Sugars Bakers Yeast 28 9/21/2010 Future: New Sources Sunlight to Biodiesel ?