What Bacteria Can Still Grow At Low Temperatures?


Do lentils need bacteria to grow?

Its for a science fair expiriment & i need help explaining why my cooked lentils didnt grow. So do lentils need bacteria to grow & why do they need it to grow?

They have bacteria in nodules in their roots called nitrogen fixing bacteria that fix atmospheric nitrogen into the soil. It helps them grow but they can absorb nitrogen in the soil if it is already there. They don't need the bacteria to grow if the soil has enough nitrogen but they are able to grow in soil that is low in nitrogen because of the bacteria in the nodules.
http://en.wikipedia.org/wiki/Nitrogen_fixation

Cooked lentils won't grow because the heat denatured proteins and killed them.

Does light or heat make bacteria grow faster?

I was just wondering what makes bacteria grow faster. Light or heat and at what Temperature or what type of light bulb would be best to use.

heat. the right temperature depends on the bacteria. Some grow at close to freezing temperatures, some grow at nearly boiling water temperauture. most grow some where in between at 75- 100 degrees Fahrenheit

How can some bacteria withstand extreme conditions?

Psychrophiles which are bacteria that grow optimally at low temperature usually have a higher content of unsaturated fatty acid which help to keep membrane in a semi fluid state, even at low temperatures. Also, enzymes of psychrophiles are known to have greater amount of alpha helix and lesser amount of beta sheet secondary structures.
Thermophiles and hyperthermophiles which are bacteria that grow optimally at very high temperature have some critical amino acid at some few locations in the enzyme molecules that allows enzymes to fold in such a way that they are resistant to high temperatures. Also, there is increased number of ionic bond between basic and acidic amino acids in the proteins compared to those in proteins of non thermophiles. They also have high saturated fatty acid content.

Some bacteria survive at high temperatures in compost. What allows them to digest nutrients and grow?

What allows the bacteria in compost to digest nutrients and grow at such high temperatures? (Beyond 60 degrees Celsius)

1. They must have a set of enzymes that do not denature up to that temperature, and are still active at that temperature
2. I'd expect to find that their DNA is G-C rich. The G-C bond would help hold it together more.

What temperature is good bacteria killed?

I always hear bad bacteria is killed at 145 degrees for a certain amount of time, but what about good bacteria. Is it killed in the same range or at higher temperatures? I hear that low temperature pasterization of milk kills off the bad bacteria and preserves some of the good bacteria and it's heated at 145 degrees for 30 minutes. Is this true or are they giving false statements to sell this milk?

Unless the bacterium has an endospore which is resistant to heat and chemicals, the thermal death time is the same for most species of bacteria, good or bad. Pasteurization of milk is intended to kill pathogenic bacteria typically found in milk. The standards for the quality of milk is set by state and federal agencies. Those bacteria found in pasteurized milk are considered thermoduric (tolerate the pasteurization temperature) and psychrophilic (can grow at refrigeration temperatures) and will eventually cause the milk to spoil. With ultra-pasteurization, milk does not have to be refrigerated.

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