Question

GROUP (Report 1 Growth Curve 1) The following table shows the measurements of bacterial growth in a specific period by the color Spectrophotometer Time time 3 hour Growth measurement 7.56 7.56 30.25 32.25 6 hour 9 hour 12 hour 32.25 15 hour 2.69 A) Draw the growth curve for bacteria B) Write a discussion of the results (Abbreviator) 2) The plate was inoculation with a fungal disc 1 cm, and then incubated for 7 days and 25C * The following image shows the growth of the fungus during this period: Qlise a ruler to measure the Diameter of the fungal growth GROUPS (Report 2) The importance of microorganisms in various industries (enzymes+ Antagonism A) Write the name of the bacterial enzyme in each of the following Petri dishes: B) Writing a discussion of the dish (C) only.

Answer 1

Report 1

A. The given data was used to plot the bacterial growth curve.

Bacterial growth curve Stationary Log Death phase Absorbance Lag 0 2 4 6 8 10 Time (hr) 12 14 16 18 20

B.

This bacterial growth curve reflects the events in bacterial population when they are grown in a closed system of microbial culture of fixed volume (i.e. batch culture).The typical growth curve for population of cells can be divided into several distinct phases called the lag phase, log phase, stationary phase and death phase.

Lag phase: When a microbial population is inoculated into a fresh medium, growth usually does not begin immediately but only after a period of time called the lag phase. The inoculum should be of log phase.

Log phase (exponential phase):In this phase, bacterial cell numbers doubles during each unit time period (i.e. generation time). Here, the log phase is of 3hrs (3-6hr).

Stationary phase:The number of new cells produced equals to the numer of cells that die, resulting in a steady state. In batch culture, exponential growth cannot occur indefinitely because the essential nutrients of the culture medium are used and waste products of organisms accumulate in the environment.

Death phase:If incubation continues after a bacterial population reaches the stationary phase, the cells may start dying. Cell death may be due to cell lysis.

Report 2

1. Enzyme: Lipase

Spirit blue agar is used to identify organisms that are capable of producing the enzyme lipase. Spirit blue agar contains an emulsion of olive oil and spirit blue dye. Bacteria that produce lipase will hydrolyze the olive oil and produce a halo around the bacterial growth.

2. Enzyme: Proteolytic enzyme Caseinase (In dairy)

Proteolytic bacteria use the enzyme caseinase to hydrolyze casein and form soluble nitrogenous compounds displayed as a clear zone around colonies.

3. Enzyme: α-amylase

Starch agar is a general-purpose, nutrient medium used for the cultivation of microbes. An inoculum from a pure culture is streaked on a sterile plate of starch agar. After inoculation and overnight incubation, iodine reagent is added to detect the presence of starch. Iodine reagent complexes with starch to form a blue-black color in the culture medium. Clear halos surrounding colonies is indicative of their ability to digest the starch in the medium due to the presence of alpha-amylase.