<prompt> Psychrophilic bacteria grow best at which of the following temperatures?20degC30-37degC50-0degC60degC  <response>: Ans. a 20degC Ref. Ananthanarayan Microbiology 7thpg. 22On the basis of temperature relationship, microorganisms are broadly divided into three groups:Phychrophiles grow optimally at0-5degCMesophiles at2045degCThermophiles 55degCMany yeasts and molds and, certain bacteria grow well in acidic media pH 5.0 or lower while most bacteria require a pH near neutrality 6.5-8.0 for optimal growth. 