Environmental Factors in Microbiology PDF

Mostmicrobes growinmoderate conditions e nvironmental growunderharsh Extremophiles c onditions Optimal range of result environmental parameters...

Mostmicrobes growinmoderate conditions e nvironmental growunderharsh Extremophiles c onditions Optimal range of result environmental parameters inthebestgrowth Osmosis and Water Activity Changesinsolute resultsinchangesinosmotic concentrations c oncentrations Typesofsolution 1 Hypotonicsolution soluteconcentrationoutsidethe lower cellthaninsidethe cell cellleadingtocellburst waterentersthe 2 Hypertonicsolution conoutsidethe solute higher cellthan the inside cell cellleadingtoshrinkcell leavethe water 3Isotonicsolution and conoutsid solute same inside cell the movement not water is effected Adaption to hypotonicsolution iscell wallpreventbursting aprotistsusecontractilevacuoles Mschannelsinplasmamembraneallowsolutestoleave sensitive simechano Wateractivity aw measureofthe degreeofwater availability lowerwateractivity waterisboundandnot available Types of microbes 1 erotolerant thatwithstandhighsolutecon microbes  tolerant 2Osmo thatcan microbes wide over grow optimallyathigher rangesofawbut levels Halophiles typeofosmophilesthat requireabout.o.amNacl Extremehalophiles requirebetween3m to6.2MNaclsalt pH and Hydrogen Ion pH ameasureofrelativeacidityofsolution Typesofmicrobes isAcidophiles pH0to5.5 aNeutrophiles mostbacteriaandprotists 3Alkalophiles pHsto11.5 Note Most fungi acidic prefer about.ph4to environment 6 Temperature regulatetheir Microbescannot internaltemperature affect Temperature activity enzyme Below temp optimum activitynotfunctional slow Above o ptimumtemp inhibit activitydenature andoptimal NoteCardinaltempsareminimummaximum Typesofmicrobes 1esychrophiles orto20C aesychrotrophs orto3sec 3Mesophiles 20Ctouse us Thermophiles usto85C 5 Hyperthermophiles 85Cto100C Adaption of thermophiles 1Heatstableencymes 2proteinsynthesissystemfunctionathightemp 3more andmorebranchedfatty saturated acidsintheir m embranes Oxygen Concentration Typesof Microbes 1obligateaerobe requireor killedinpresenceofor 2obligateanaerobe usually aerophile require2to 3Micro 10 or ofordo aFacultativeanaerobes growbetterinpresence not requirea withorwithoutor 5Aerotolerantanaerobes grow Oxygenand Bacterial Growth Positive growth dotsatthe top growth Negative dotsatthe bottom Pressure surfaceliveata pressureof 1atm onlandandwater Microbes somebacteriaandarchaealiveindeep seawithvery highpressures Types ofmicrobes 1Barotolerant affected unfavorably by increased pressure 2seizophilicbarophilic requireshigh for p ressure growth their fatty membrane aremoreunsaturatedand acids shorter Radiation 1 Ionizingradiation xraysand rayscausesmutationsthatindirectlyresultindeath gamma disrupts of by anddestroysring structure molecules breaking bond c hemical H structure NoteBacterialendosporesareresistanttoionizing radiation 2Ultraviolet UV radiation nmbecauseit isabsorbed Mostlethalwavelengthis260 byDNA DamagedDNAcan berepairedbyseveralmechanisms