Putting Microbes to workThursday, April 14

What role DO microbes play in industry?

Industrial Microbes: What are they?• Microorganisms • Grown on a ___________________(usually) to

• to produce some kind of _______________________________.• to carry out an important _______________________________.

• These microbes are already capable of carrying out metabolic process that the industry needs– the main goal is ___________________ of the of the product of interest.

Figure 25.1

Industrial Microbes: What are they?• Able to ___________ in a large scale culture.

• Produce _____________ so that it can be easily inoculated into a large vessel.

• Grow __________ and produce designed product __________________.

Industrial Microbiology: Terminology__________________ – any large scale microbial process

(whether or not it is a fermentation in a biochemical sense)

_________________ – vessel in which an industrial microbiology process is carried out

NOTE: In industrial microbiology, most fermentations are _____________ processes, where as “real” fermentation (or glycolysis) is an _____________ process

Microbes and FOOD

What foods utilize microbes for their production?

Microbes and FOOD

Microbes and EtOH

“Real” fermentation, or glycolysis

http://www2.estrellamountain.edu/faculty/farabee/biobk/biobookglyc.html

Microbes and EtOH____________• Mostly made from _____________• ___________ are responsible for the fermentation of

grape juice• Types of wine

• ____________ Wine – all sugar in the grape juice are completely fermented

• ____________ Wine – sugar in the grape juice is not completely fermented, or additional sugar is added after fermentation

• _______________ wine – brandy or another alcoholic beverage is added after fermentation.

• ________________ wine – carbon dioxide (CO2) is still present from a final fermentation by the yeast directly in the sealed bottle (ex. champagne)

Microbes and EtOH

Wine Production

Figure 25.18

Microbes and EtOH

Wine Production

Figure 25.18

Microbes and EtOHWine Production

Figure 25.17

Grape transportation equipment

Tanks for fermentation

Large aging barrel Smaller aging barrel

Microbes and EtOH

_______________• Produced from fermentation of ________ or other starches• ___________ are responsible for the fermentation of grape

juice• Specific ___________ of yeast of used to obtain specific

types of beers (ex. lager vs. ale)

• Alcohol levels are _________ then wine, but CO2 levels are ______________.

Microbes and EtOH

Beer• Terminology

• ______________ – term used to describe the manufacture of alcoholic beverages from malted grains

• ___________ – prepared from germinated barley seeds, and contains enzymes needed to digest the starch of grains into sugars (brewing yeasts are unable to digest grains)

• ____________ – process that makes the fermentable liquid from which beer and ale are made

• ____________ – the aqueous mixture that results after mashing• ____________ – an herb derived from the female flowers of the hops

plant, and is added to the wort.

Microbes and EtOHM

akin

g B

eer

Malt + Water (and other starches if needed

Mashing- Cook malt (along with other starches)

Filtration

Wort

Sterilize

Filter and Cooled

Hops

Boil for several hours in copper kettles

FermentationYeast

Beer

Store (temp. and time dependent on desired flavor)

Filter

Package

Microbes and EtOH

Making Beer

The Chemistry of Beer

Microbes and Bread

- _______________ - the process of adding gas to a dough before baking to produce a lighter, more easily chewed bread.

- Leavening can be accomplished __________ (addition of gas-producing chemicals) or by ___________ (mostly yeast)

- Baker’s yeast (Saccharomyces cerevisiae) ferments carbohydrates and any sugar to produce _______.

Microbes and BreadSourdough bread- The sour taste of sourdough bread does not come

from yeast, but rather the ____________, __________________!

- Saccharomyces cerevisiae and lactobacillus live in ________________.

- Lactobacillus utilizes the by products of yeast fermentation, which results in the secretion ____________________.

- The lactic acid then prevents the bread from ______________.

Microbes and DairyYogurt• Produced by the fermentation of milk by _____________.• Bacteria convert lactose in milk to __________________.• Bacteria used:

• Streptococcus salivarius• Lactobacillus acidophilus• BL Regularis strain (Bifidobacterium lactis DN-173 010)

• If bacteria is not heat-killed, then the yogurt contains “_________________________________”

• These live cultures can be beneficial:• May help relieve ____________________________________(including

constipation, diarrhea)• Enhance the body’s ________________________.• Discourage ___________________________________________

Microbes and Dairy

Cheese- Only ingredients needed to make cheese are: milk, salt,

rennet (complex of dietary enzymes that work to coagulate milk) and _________________.

- Microbes play a very important role in ________________ and ripening the cheeses

- Modern cheeses are made with pre-selected cultures containing only a ___________________strains of microbes

- Traditional cheese are made from whey or products from previous batching, meaning that there are many many ____________________________of microbes present.- This wealth of microbial life can account for the more complex taste

that traditional cheeses have when compared to modern cheeses.

Microbes and Dairy

Cheese – Swiss Cheese - ___________________________Bacteria, specifically

Propionobacter shermanii- Digest and convert acetic acid into propionic acid (smells

like sweat) and CO2.

- The CO2 provides the _________ in Swiss cheese.

- The propionic acid provides the complex, __________ taste of Swiss cheese.

- Interesting note- Propionobacter shermanii also inhabits the human skin and helps to produce the “unwashed” odor.

Microbes and Dairy

Cheese – Blue (or bleu)Cheese- Ex. Gorgonzola- Blue color is caused by __________:

- Penicillium roqueforti- Penicillium glaucum

- Cheesemakers will actually ___________ this mold into to-be-blued cheese to encourage the growth of the mold.

- These molds not only provide the blue coloring, but they also responsible for the ___________ and ____________ of the cheese.

Microbes and DairyCheese

Making Cheese

Microbes and More

Chocolate- Chocolate comes from the seeds of the chocolate tree.- These seeds are called cacao.- To get their chocolate flavor, the cacao seeds must be

____________________, dried and roasted

Microbes and MoreChocolate

Harvest pods of cacao seeds

Split pod to reveal seeds in pulp

Cover seeds

Leave covered for days. Chemical composition change.Microbe composition changes

Dry beans

Make chocolate!

A few sources• http://www.seriouseats.com/2010/02/what-microbes-

make-cheese.html• http://smccd.edu/accounts/case/chocolate.html• http://www.chemistrydaily.com/chemistry/Bread