인간의 삶과 역사 속의 미생물

2012-1학기

강의자료 ppt-10

미생물은어떤 존재인가?

생명공학 (biotechnology)의 주체인 미생물

Use of organisms to form useful products (in in-dustrial, medical, or agricultural applications)

Biotechnology ( 생명공학 , 생물공학 )

Products of Microbial Biotechnology

• 식품 및 식품 첨가물 생산 : 발효 식품 , 아미노산 , 미생물 식품으로 이용 ( 버섯 , 미역 , 김 등 )

• 건강 ( 영양 ) 보조제 생산 : 식이섬유 , 비타민 , 미생물 건강( 영양 ) 보조제로 이용 ( 유산균 , 클로렐라 , 스피루리나 , 효모 등 )

• 의약품 생산 : 항생물질 , 호르몬 , 스테로이드 등• 효소 생산 : 산업용 효소 , 세제 첨가용 효소• 화학제품 생산 : 바이오폴리머 ( 생분해 플라스틱 등 ),

시트르산 , 아세톤 , 글리세린 , 에틸알코홀 , 초산 등• 연료 생산 : 메탄가스 , 에틸알코홀 , 수소 가스 등• 살충제 생산 : 미생물 살충제• 광물 정제 : 구리 , 금 , 납 등

Combinational Biology in Biotechnology

식품 및 식품 첨가물 생산

• Wine• Brewing, distilling, and commodity Alcohol• Vinegar• Citric acid and other organic compounds• Yeast as a food and food supplement• Mushrooms, spirulina, chlorella, edible sea-

weeds as a food source

Products for food industry

Industrial uses of yeast and yeast products

• Amino Acids– Used as feed additives in the food industry– Used as nutritional supplements in nutraceutical indus-

try– Used as starting materials in the chemical industry– Examples include

• Glutamic acid (MSG)• Aspartic acid and phenylalanine (aspartame [Nutrasweet])• Lysine (food additives)

Vitamins and amino acids: Amino acids

Amino acids used in the food industry

건강 ( 영양 ) 보조제 생산

Industrial uses of yeast and yeast products

• Production of vitamins is second only to antibiotics in terms of total pharmaceutical sales– Vitamin B12 produced exclusively by microorganisms

• Deficiency results in pernicious anemia ( 악성빈혈 )

– Riboflavin (VB2) can also be produced by microbes

Vitamins and amino acids: Vitamins

VB12 Ri-boflavin

의약품 생산

• Steroids– Are derivatives of sterols

– Are important animal hormones with medicinal uses• Corticosteroids reduce inflammation, and help control aller-

gies, inflammation and arthritis

• Estrogens and androgenic steroids play a role in human fertil-ity and can stimulate production of muscle mass

– Production of steroids by chemical process is costly• Use microbes to reduce cost (biotransformation)

Steroids and other biotransformations

Sterol

Cortisone production using a microbe: Biotransforma-tion

효소 생산

• Exoenzymes– Enzymes that are produced in such large amounts

that they are excreted into the medium instead of be-ing held within the cell; they are extracellular

– Can digest insoluble polymers such as cellulose, pro-tein, and starch

Enzymes as industrial products

• Enzymes are produced from fungi and bacteria– Bacterial proteases are used in laundry detergents

(can also contain amylases, lipases, and reductases)• Isolated from alkaliphilic bacteria

• Amylases and glucoamylases are also commer-cially important– Produce high-fructose syrup

Enzymes as industrial products

Microbial enzymes and their applications

• Extremozymes– Enzymes that function at some environmental ex-

treme (i.e., pH or temperature)– Produced by extremophiles

Enzymes as industrial products

Examples of extremozymes: Acid-tolerant enzymes

화학제품 생산

Industrial uses of yeast and yeast products

Biopolymers

• Poly-β-hydroxybutyric acid (PHB)– Bioplastic (bacterial plastic)

• Dextrin (a group of low-molecular-weight carbohydrates produced by the hydrolysis of starch or glycogen), cyclodextrin, and other polysaccharides– Used to modify flow characteristics of liquids and to

serve as gelling agents

• The recalcitrance of plastics has fueled re-search efforts into a biodegradable alter-native (biopolymers)

Bacterial plastics

Bacterial plastics

Poly-β-hydroxyvalerate poly-β-hydroxybutyrate

Bacterial plastics

Shampoo bottle made of the PHB/PHV copolymer

• Used for emulsification, increasing detergency, wetting and phase dispersion, and solubilization

• Important in bioremediation, oil spill dispersion, and enhancing oil recovery

• Many have antibacterial and antifungal activity; some inactivate enveloped viruses

Biosurfactants

• > 50,000,000,000 liters of ethanol are produced yearly for industrial purposes– Used as an industrial solvent and gasoline supplement

Commodity alcohol production

Ethanol production plant, Nebraska, USA

연료 생산

• > 50,000,000,000 liters of ethanol are produced yearly for industrial purposes– Used as an industrial solvent and gasoline supplement

Commodity alcohol production

Ethanol production plant, Nebraska, USA

Gasohol

Estimates of CH4 released into the atmosphere

Biosynthesis of methane

Certain green algae (e.g. Botryococcus braunii )

Botryococcus braunii excreting oil droplets

Production of petroleum by some microbes

살충제 생산

• Biological agents, such as bacteria, fungi, viruses, or their components, which can be used to kill a susceptible insect

Microbial insecticides (biopesticides)

• Bacillus thuringiensis– Produces a parasporal body during sporulation as

an intracellular protein toxin crystal– Parasporal body

• Acts as microbial insecticide (Bt toxin) for specific groups of insects

– Bt toxin • used for over 40 years• unlike chemical insecticides, does not accumulate in en-

vironment

Microbial insecticides (biopesticides): Bacteria as biopesticides

Toxic parasporal crystal in Bacillus thuringiensis

Activation of Bt toxin

Action mechanism of Bt toxin

광물 정제

• In microbial leaching, low-grade ore is dumped in a large pile (the leach dump) and sulfuric acid is added to maintain a low pH

• The liquid emerging from the bottom of the pile is enriched in dissolved metals and is transported to a precipitation plant

• Bacterial oxidation of Fe2+ (ferrous iron, 2 가철 ) is critical in microbial leaching as Fe3+ (ferric iron, 3 가철 ) itself can ox-idize metals in the ores

Microbial leaching of ores

Microbial leaching of low-grade copper ores

Microbial leaching

• Microbes are also used in the leaching of uranium and gold ores

Gold bioleaching tanks in Ghana

Microbial leaching of ores

기타 역할

• Microbes for nanotechnology– e.g., use of diatom 3-D structures as templates– e.g., use magnetosomes from magnetotactic bacteria

in magnetic resonance tomography (MRI) applications and as probes to detect cancer

Microbes as products for nanotechnology

• Living microbes, enzymes or organelles are linked to electrodes to detect specific sub-stances– detection is done by converting biological reaction

products into electrical currents

• Have a broad range of applications

Biotechnological applications: Biosensors

생명공학에 필요한새로운 유전자 탐색

• Gene mining– The process of isolating potentially useful novel genes

from the environment without culturing the organism – To do so, DNA (or RNA) is directly isolated from the

environment, cloned into appropriate expression vec-tors, and the library screened for activities of interest

Mining genomes

* Metagenome - The total genome of all the cells present in a particular environment

Metagenomic search for useful genes in the environment

형질전환생물 제작과 미생물

• Engineering metabolic pathways in bacteria• Genetic engineering of animals• Gene therapy in humans• Transgenic plants in agriculture

Transgenic organisms

• Transgenic organism– An organism that contains a gene from another organism

– Also refers to genetically engineered organisms whether

or not they contain foreign DNA

• The production of small metabolites by genetic en-gineering typically involves multiple genes that must be coordinately expressed

• Pathway engineering– The process of assembling a new or improved biochemi-

cal pathway using genes from one or more organisms

Transgenic organisms: Engineering metabolic pathways in bacteria

• Genetic engineering can be used to develop transgenic animals

• Transgenic animals are useful for – Producing human proteins that require specific post-

translational modifications– Medical research– Improving livestock and other food animals for human

consumption

Transgenic organisms: Genetic engineering of animals

A piglet that fluoresces green under blue light

Fast-growing, genetically engineered salmon

• Gene therapy: treatment of a disease caused by a dysfunctional gene by introducing a functional copy of the gene

• Many human genetic diseases are known and gene therapy holds promise for tackling these dis-eases

• The use of recombinant DNA technology and con-ventional genetic studies allows for the localization of particular genetic defects to specific regions of the genome

Transgenic organisms: Gene theraphy in humans

• Many successes in plant genetic engineering

- Several transgenic plants are in agricultural production

• The plant pathogen Agrobacterium tumefaciens can be used to introduce DNA into plants

• A. tumefaciens contains the Ti plasmid, which is responsible for virulence

• The Ti plasmid contains genes that mobilize DNA for transfer to the plant

Transgenic organisms: Transgenic plants in agriculture

Production of transgenic plants using A. tumefaciens

• Tobacco was the first genetically modified (GM) plant to be grown commercially– 2005 estimates that > 1 billion acres of agricultural land

are growing GM crops

• Several areas are targeted for genetic improve-ments in plants including herbicide, insect, and mi-crobial disease resistance as well as improved product quality

Transgenic organisms: Transgenic plants in agriculture

Transgenic plant with herbicide resistance

• One of the most widely used approaches for ge-netically engineering insect resistance in plants involves the introduction of genes encoding the toxic protein of Bacillus thuringiensis (Bt toxin)

Transgenic organisms: Transgenic plants in agriculture

Transgenic plant with insect resistance

• Improving product quality is another target area of genetic engineering of plants – e.g., spoilage delay

• Transgenic plants can also be employed to pro-duce human proteins for medical use– e.g., insulin, interferon, antibodies, vaccines

Transgenic organisms: Transgenic plants in agriculture

• Industrial ecology– Concerned with tracking flow of elements and

compounds through natural world (biosphere) and social world (anthrosphere)

• Microbiologists must:– Understand potential impacts of new products and

processes on the broader society as well as on microbiology

– Communicate effectively with the various “societal stakeholders” about the immediate and longer-term potential impacts of biotechnologies

Impacts of microbial biotechnology