Bacterial Nutrition and Growth PDF

1 2 3 4 5 6 7 8 9  pH and Microbial Growth pH – measure of [H+] each organism has a pH range and a pH optimum acidophiles – optimum in pH range 1-4 alkalophiles – optimum in pH range 8.5-11 lactic acid bacteria – 4-7 Thiobacillus thiooxidans – 2.2-...

1 2 3 4 5 6 7 8 9  pH and Microbial Growth pH – measure of [H+] each organism has a pH range and a pH optimum acidophiles – optimum in pH range 1-4 alkalophiles – optimum in pH range 8.5-11 lactic acid bacteria – 4-7 Thiobacillus thiooxidans – 2.2-2.8 fungi – 4-6 internal pH regulated by BUFFERS and near neutral adjusted with ion pumps Human blood and tissues has pH 7.2+0.2 10 11 12 13 Environmental factors and growth 1. Osmotic Effect and water activity organisms which thrive in high solute – osmophiles organisms which tolerate high solute – osmotolerant organisms which thrive in high salt – halophiles organisms which tolerate high salt – halotolerant organisms which thrive in high pressure – barophiles organisms which tolerate high pressure – barotolerant 14 15 16 17 18 19 20 21 22 23 24 Aquachelin 25 26 Need very little amount but critical to cell function. Often used as enzyme cofactors 27 Organic compounds, required in very small amount and then only by some cells 28 29 30 31 32 33 34 Environmental factors and growth 4. Oxygen anaerobes lack superoxide dismutase and/or catalase anaerobes need high -, something to remove O2 chemical: thioglycollate; pyrogallol + NaOH H2 generator + catalyst physical: removal/replacement 35 Special Culture Techniques Candle Jar 36 Special Culture Techniques Gas Pack Jar Is Used for Anaerobic Growth 37