What is bioconversion Bioconversion is the conversion of organic materials, such as plant or animal waste, into usable products or energy sources by biological processes or agents, such as certain microorganisms or enzymes.(wikipedia dictionary). Things to consider: What to convert. what to use What to get

What bioconversion can do Bioconversion can be carried out physically, thermochemically and biologically. This process has been applied in the production of foodstuffs, organic chemicals and energy. Biological methods for bioconversion has given priority with the use of microorganisms as less expensive yet effective agents. This process is also known as fermentation.

Importance group of bacteria in bioconversion Lactic acid bacteria Acetic acid bacteria Bacteria of alkaline fermentation http://bioconversion.blogspot.com/

Conversions by Acetic Acid bacteria A second group of bacteria of importance in food fermentations are the acetic acid producers from the Acetobacter species. Acetobacter are important in the production of vinegar (acetic acid) from fruit juices and alcohols. The same reaction also occurs in wines, oxygen permitting, where the acetobacter can cause undesirable changes – the oxidation of alcohol to acetic acid. The vinegar process is essentially a two stage process, where yeasts convert sugars into alcohol, followed by acetobacter, which oxidise alcohol to acetic acid. Acetic acid fermentation Acetobacter convert alcohol to acetic acid in the presence of excess oxygen. The oxidation of one mole of ethanol yields one mole each of acetic acid and water; C2H5OH   CH3CHO +H2O  CH2CH(OH)2 CH3COOH + H2O ethanol acetaldehyde hydrated acetaldehyde acetic acid

1.Usage - Acetic acid is a chemical reagent for the production of chemical compounds. The largest single use of acetic acid is in the production of vinyl acetate monomer, closely followed by acetic anhydride and ester production. The volume of acetic acid used in vinegar is comparatively small. 2. Type of culture – highly aerated submerged processes. 2. Raw material-diluted purified ethanol from grape juice, apple juice, barley malt etc. 3. Factors influence-Oxygen supply and the concentration gradients of ethanol and acetate.

1. Lack of oxygen lack of O2 will killed the bacteria because they are extremely sensitive. to overcome this problem, has to use efficient aeration efficient aeration can be achieved with the used of compressed air and proper mechanical device. for efficient aeration also have to consider shear stress imparted by the fluid and the microorganisms itself. the efficiency depends on the ratio between the energy input necessary per unit weight of O2 transferred to the culture. 2. Over-oxidation when there is over-oxidation, acetic acid will convert to CO2 and H2O. will decrease acetic acid production. have to maintain acetic acid concentrations above 6% of the total culture. and avoid the total depletion of ethanol.

Citric Acid Production 1. Usage- has long been used in soft drinks manufacture as an acidulant, as an aid to jam setting and as a general additive in the confectionery industry. 2. Bacteria used – Aspergillus niger or Candida yeast 3. Culture method – Surface culture method was used using A. niger and submerged method using Candida yeast. 4. Raw material; Molasses 5. Factor influence using surface culture method. sensitive to Mn2+ concentration. Production reduced at Mn2+ low as 3 mg/L Oxygen supply pH should maintain below 2.0. At higher values, A.niger accumulates gluconic acid rather than citrate.

5. Biochemistry of production Involves few steps Breakdown of hexoses to pyruvate and acetyl CoA. The anaplerotic formation of oxaloacetate from pyruvate and CO2 The accumulation of citrate within the tricarboxylic acid cycle - The key enzyme is pyruvate carboxylase, constitutively produced in Aspergillus species.

Advantages of bioconversion While focusing much of their attention on building advanced E-Flex technology to reduce the need for liquid fuels, GM certainly recognizes that ethanol is going to be a major form of renewable fuel globally during most of the coming century.

Convert solar energy into liquid fuels

Reduce Greenhouse Gases Please read article entitle “Carbon’s New Math” to get full picture on this Advantages.

Remediate ecological disaster 1. forest density that is 4 to 10 times historic norms – creates conditions that exacerbate droughts leading to forest fires and bug infestations 2. municipal solid wastes – is getting out of control necessitating bigger landfills that are further away from our urban centers. This excess waste contributes to land, water, and air pollution 3. Rural agricultural residues and damaged crops could have a higher value as soil amendments and biomass feedstock

Bioconversion technology for biofuel production Two methods are available; The fermentation of biomass for biogas The fermentation of biomass for ethanol The production of biogas (methane) Can be achieved in three steps: Acid production (hydrolysis) Acid reduction Methane production

Bioconversion technology for ethanol production It is similar to the technology of manufacturing drinkable alcohol. In many countries, alcohol has been used in engine in a mixture of petrol and alcohol (10-20%). The largest program PROALCOL in Brazil, the ethanol was mixed with petrol in the ratio 80:20. Cannot use pure ethanol since has low calorific value, 40% lower than petrol.

Basic biology and technological method biologically, alcohol was formed when there is an action of microorganisms in the form of yeast anearobs on sugar containing solution. sugar + yeast ethanol + carbon dioxide C6H12O6 + yeast 2C2H5OH + 2CO2 For commercialization of ethanol production, two different types of substrates are available for fermentation. Both substrates need different type of pre-treatment. Sugar containing biomass Starch containing biomass Starch (C6H10O5), is first of all converted into glucose.

Starch (C6H10O5), is first of all converted into glucose. Example of sugar containing raw products are sugarcane, sugarbeet, sugar millet and fodder beet. Example of sugar containing starch are maize, grain, cassava and potato. Technologically, there are differences in fermentation process of sugar or starch containing raw materials.

For sugar containing plants, the juice of sugar is extracted and processed into sugar. For starch containing plants, the starch is first extracted and mixed with warm water. This resulting in the formation of paste like substances. The paste is then converted into glucose in dexternisation saccharination process. The glucose then will be disintegrate in the disintegration process. Glucose from both process then fermented in the fermenter and ethanol finally obtained through the process of distillation.