Effect of temperature on the growth rate of amylolytic strains of Geomyces pannorum

Our previous researches demonstrated per-spective of search for low-temperature amylase producers in cave microbial communities. In pre-sent work effect of temperatures in the range of +9 to +30 °C on the growth rate of eight amylolytic strains of Geomyces pannorum isolated from low-temperature karst cave Karaulnaya-2 has been studied. All the strains were found to be psychrotolerant with the maximal growth tempera-ture at +30°C and the optimal growth temperatures in the range of +18.5 to +25.3 °C. Growth rate at the optimal temperature varies from 4.2 to 17.5 mi-crometer per hour per one hyphae depending on the strain. No correlation between optimal tempera-ture value and value of growth rate at optimal tem-perature was found. The average optimum temper-ature for eight strains is +22.2 °C and the average growth rate at the optimal temperature is 10.2 mi-crometer per hour. In most cases effect of temper-ature on growth rate can be adequately described by the Ratkowsky et al. (1983) model with the coef-ficients of determination R2 in the range of 0.987 до 0.999. For some strains the temperature curves fits the Ratkowsky model only near extremum. The results of the research demonstrate possibility to produce fungal amylase at temperature about 15 degrees lower then temperature which is used now for such producers as Aspergillus awamori. This allows to reduce energy costs of amylase produc-ing and to slow down growth of extraneous mesophilic microflora in case of microbial contami-nation of fermenter.