Evaluation of the growth medium of a new ice-nucleating-active Pseudomonas: A response surface methodology approach

ABSTRACT

Aims@#Attention to ice nucleation proteins has increased for more than two decades. Ice nucleation proteins have been utilized for artificial snow-making known as Snowmax™, cryopreservation of tissues and cells, and cloud condensation nuclei. There is a direct relationship between bacterial growth and ice nucleation activity. Therefore, the optimization of the culture medium seems necessary.@*Methodology and results@#The effect of different carbon and nitrogen sources on the growth of a new native Pseudomonas sp. IRL.INP1 was evaluated by using fractional factorial design, the path of the steepest ascent experiment and central composite design. Ice nucleation activity, biomass and whole-cell protein were identified afterward. The model predicted by response surface methodology indicated that the maximum bacterial growth was observed when sucrose, ammonium sulfate [(NH4)2SO4] and manganese (II) (Mn2+) were utilized at 12.46 g/L, 321.97 mg/L and 938.09 µM, respectively. Also, 1.10 g/L biomass and 0.85 µg/µL whole-cell proteins were gained, and the isolate showed ice nucleation activity 31 sec sooner after optimization.@*Conclusion, significance and impact of study@#Ice nucleation proteins are growth-dependent and the growth condition optimization leads to higher bacterial cells growth. Therefore, best bacterial growth was obtained when proper carbon and nitrogen sources were used, and ice nucleation activity was observed in shorter time. This is the first study concerning ice nucleation activity optimization using different carbon and nitrogen sources.