Statistical optimization of medium components for extracellular protease production by an extreme haloarchaeon, Halobacterium sp. SP1(1).

Aims:  Optimization of medium components for extracellular protease production by Halobacterium sp. SP1(1) using statistical approach. Methods and Results:  The significant factors influencing the protease production as screened by Plackett–Burman method were identified as soybean flour and FeCl3. Response surface methodology such as central composite design was applied for further optimization studies. The concentrations of medium components for higher protease production as optimized using this approach were (g l−1): NaCl, 250; KCl, 2; MgSO4, 10; tri-Na-citrate, 1·5; soybean flour, 10 and FeCl3, 0·16. This statistical optimization approach led to production of 69·44 ± 0·811 U ml−1 of protease. Conclusions:  Soybean flour and FeCl3 were identified as important factors controlling the production of extracellular protease by Halobacterium sp. SP1(1). The statistical approach was found to be very effective in optimizing the medium components in manageable number of experimental runs with overall 3·9-fold increase in extracellular protease production. Significance and Impact of the Study:  The present study is the first report on statistical optimization of medium components for production of haloarchaeal protease. The study also explored the possibility of using extracellular protease produced by Halobacterium sp. SP1(1) for various applications like antifouling coatings and fish sauce preparation using cheaper raw material.