• FOOD BIOTECHNOLOGY

• FERMENTATION,

• BATCH AND CONTINUOUS FERMENTATION

• SOLID STATE FERMENTATION

• FERMENTOR DESIGN

• PRESENTED BY

• N.INDRA .

• FERMENTATION

• Fermentation is the oldest form of biotechnology, essentially consisting of transformation of the simple raw materials into value added amazing range of products by utilizing the growth of microorganism.

• The basic purpose of micro organisms to break down the organic compounds is to get energy for their metabolic process.

• Some fermented products

• BATCH FERMENTATION

• A batch fermentation is regarded as a closed system.

• The sterile nutrient culture medium in the bioreactor is inoculated with micro organisms.

• The incubation is carried out under optimal physiological conditions.

• It may be necessary to add acid or alkali to maintain pH and antifoam agents to minimize foam under optimal conditions for growth.

• Under optimal conditions for growth the following typical phases of growth, are observed in batch fermentation.

• PHASES

• Lag phase

• Acceleration phase

• Logarithmic (log) phase (exponential phase)

• Deceleration phase

• Stationary phase

• Death phase

• LAG PHASE

• Initial period of culturing after inoculation is referred to as lag phase.

• During the lag phase, the micro organisms adopt to the new environment avaliable nutrients, pH etc.,

• There is no increase in the cell number, although the cellular weight may slightly increase.

• PHASES GRAPH

• Acceleration phase

• It is a brief transient period during which cells start growing slowly.

• This phase connects the lag phase and log phase.

• Log phase

• The most active growth of micro organisms and multiplication occur during log phase.

• The cells undergo several doublings and the cell mass increase when the number of cell or biomass is plotted against time on a semi logarithmic graph, a straight line is obtained.

• Growth rate of microbes in log phase is dependent on substrate (nutrient supply)

• STATIONARY PHASE

• The substrate in the growth medium gets depleted and the metabolic and products that are formed inhibit the growth, the cells enter the stationary phase.

• The microbial growth may either slow down or completely stop.

• The biomass may remain almost constant during this phase

• Death phase

• The cells die at an exponential rate.

• In the commerical and industrial fermentation, the growth of the microbes is the end of the log phase or just before the death phase begins and the cells harvested.

• CONTINUOUS FERMENTATION

• It is an open system.

• It involves the removal of culture medium continuously and replacement of this with a fresh sterile medium in a bioreactor.

• Both addition and removal are done at the same rate so that the working volume remains constant.

• Homogenously mixed Bioreactors

In this type, the culture solution is homogenously mixed

The bioreactors are of two types

• Chemostat bioreactors

The concentration of any one of the substrate is adjusted to control the cell growth and maintain a steady state.

• Turbidostat bioreactors

In this case, turbidity measurement is used to monitor the biomass concentration.

The rate of addition of nutrient solution can be appropriately adjusted to maintain a constant cell growth.

• SOLID STATE FERMENTATION

• Most fermentation technologies using microbes employ a fairly dilute medium where the substrate to be fermented is diluted in water and then inoculated with desired microbes.

• Some fungai can grow in conditions without free water.

• In this case the moisture required by the fungus exists than absorbed or complex form in the solid matrix , often ranging between 10% and 80% processes which exploit the growth of fungai in this type of system are designated solid state fermentation.

• EXAMPLES FOR SOLID SUBSTRATE FERMENTATION

• FERMENTOR DESIGN

• WINE MAKING FERMENTOR

• FERMENTOR DESIGN

• A fermentor is a device in which the organisms are cultivated and motivated to form a desired product

• Closed vessel or containment designed to give a right environment for optimal growth and metabolic activity of the organism

• Fermenter: for microbes/ Bioreactor : for eukaryotic cells

• Size variable ranging from 20-250 million litres or more.

• Large scale production (10-100L to1000-million L capacity)

• Regular monitoring for physical, chemical biological parameters is done through controlled systems of the fermentor, because these parameters influnces the growth of the microbes.

• As per requirements and use of types of microorganisms there are different types of fermentors available.

• The most common among these is stirred tank fermentor where impellers used to stirr the medium.

Helps to meet requirements of:

pH

temperature

aeration

agitation

drain or overflow

control systems

sensors

cooling to achieve maximum microbial yield

• The increasing concentration of microbial cells will deplete the dissolved O2 concentration resulting in creation of anaerobic conditions.

• The microbial growth will simultaneous decline in product production.

• The forced aeration favours rapid growth of micro organisms.

• A pH fitted with fermentor regularly monitors the pH and maintains at optimum by adding acid or alkali.

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