Materials and methods
2.1. Organism and growth conditions
Bacillus spp., potent protease (SBP-114) and lipase (RK-2) producers
were isolated from the soil by enrichment and selective
screening on skim milk agar plate and tributyrin agar plate
respectively. These strains were identified by MIDILABS (New York,
DE, USA) as Bacillus licheniformis and B. subtilus based on 500-bp
analysis and on the partial 16S rRNA gene alignment with the Gene
Bank database (ncbi, 2012) (). The organisms were cultivated at
37 1
C in a bacteriological incubator for 24 h and subsequently
maintained at 4
C in a B.O.D incubator (Yorko, Deluxe-10) by
routine transfers on nutrient agar slants at pH value of 7.0.
2.2. Enzyme production in a bioreactor
The enzymes used for dehairing (protease) and degreasing
(lipase) were produced and optimized in a 300 L stirred bioreactor
(Scigenics, India) with a working volume of 220 L, separately. The
modified base medium (pH-7) used for protease production contained
(gL
K
2
HPO
4
1
): wheat bran (2); soybean meal (15); KH
(3.0); Na
2
SO
4
(2.0); and MgSO
4
.7H
O (0.10). The medium
used for lipase production contained (g/L): sunflower oil (2);
glucose (2); peptone (15); NH
4
NO
3
2
2
(3.0); and MgSO
O
(0.8 mM) (pH 8). These media were sterilized separately in situ at
121
C for 20 min and inoculated with 2.0% of the seed inoculum
(nutrient broth) (OD
660nm
PO
y 0.600). Fermentation for protease
production was carried out at 37 1
4
4
(1.0);
.7H
C for 24 h and for lipase
2