Statistical optimization of cultural conditions of an halophilic alpha-amylase production by halophilic Streptomyces sp. grown on orange waste powder

A newly isolated strain from the water of the salt marsh of Ain Mlila in Algeria identified as Streptomyces sp. 20r was investigated for its potential to produce amylolytic enzymes. The production optimization of α-amylase using an agroindustrial residue (orange waste) as the sole carbon source was performed with statistical methodology based on Plackett–Burman experimental designs. Among the various parameters screened, the effects of various carbon and nitrogen sources were investigated. The production of the α-amylase, proteins and biomass was achieved using the statistical method of Plackett–Burman design at N=24, namely 24 experiments and 23 factors in which 19 are real ones and 4 dummy. The production medium is prepared using orange waste powder at 30 °C under agitation. Statistical analysis showed that the changes in substrate concentration (5–15%), NaCl (0–6.5%), inoculum size (5–10%) and pH (5–9) were positively affecting the production and giving the highest level of α-amylase activity corresponded to 8.26 U/mL in submerged fermentation after 5 days of cultivation.