You are the chief research officer of RP Food Biotech Inc. The company has decided to look at alternatives to yeast cells (Saccharomyces
cerevisiae) for the production of alcoholic beverages. You are to answer a series of questions to assess the feasibility of production of such a beverage. One particular product considered is a high alcoholic-content yogurt drink. Instead of yeast cells, the company is considering the bacteria
Zymomonas mobilis
as shown in Figure 1.
Z. mobilis
is a Gram negative, facultative anaerobic, non-sporulating, polarly-flagellated, rod-shaped bacterium.
Figure 1:
Zymomonas mobilis
Some characteristics of
Z. mobilis
include:
- Produces 2.5X more ethanol than yeast cells
- High ethanol tolerance of up to 16% (v/v)
- Able to ferment onlysucrose,glucose, andfructose
- Is an unwanted water-borne bacterium in beer that creates an estery-sulfury flavor due to the production of acetaldehyde and hydrogen sulfide
- Optimum growth temperature is 25°C to 30°C
- Degrades sugars to pyruvate using the Entner-Doudoroff pathway. The pyruvate is then fermented to produce ethanol and carbon dioxide as the only products
- Has a GRAS (Generally regarded as safe) status
With reference to the information provided, answer the following questions:
A) Provide the culture conditions necessary for
Z. mobilis
to produce ethanol for the industrial production of alcohol beverages, taking into account the fermentation vessel, fermentation mode and environmental parameters.
(10 marks)
A)
The idea to manufacture high alcoholic content yogurt was inspired from an alcoholic beverage from Mexico called Pulque, as shown in Figure 2.
Figure 2: Mexican Pulque
Pulque is an alcoholic beverage made from the fermented sap of the agave plant found in central Mexico. It has the color of milk, viscous in consistency, and a sour yeast-like taste.The microorganisms present in the fermentation culture of pulque produces three metabolic products, namely lactic acid, ethanol and extracellular polysaccharides (EPS). The manufacture of this alcoholic yogurt drink would also require the production of these metabolic products.
Discuss whether
Z. mobilis
can be used to manufacture the alcoholic yogurt drink. Explain your response based on the fermentative biochemistry associated with
Z. mobilis, and the production of lactic acid, ethanol and/or EPS.
(6 marks)
c)
Z. mobilis
is only able to utilize sucrose, glucose and fructose as a carbon and energy source. This narrow spectrum of substrate types used for respiration and fermentation has limited the application of this bacterial species for the production of metabolic products. Alternative saccharides must be considered if
Z. mobilis
is used to produce the yogurt drink. Select a suitable saccharide substrate that can be used by
Z. mobilis
and discuss how recombinant DNA technology can be applied to help this bacteria utilize this substrate for respiration.
(10 marks)
Comments:
i need 500 words, so pls split my words as follows
A) 50 words
B) 150 words
C) 300 words
can I show you my existing answers so that you can add on please, I dont think I need paraphasing