Aspergillus sp. is considered to be a good source of protease. Medium optimization is essential for each isolate in order to maximise the protease production. In the present study, different media were evaluated for maximising protease biosynthesis under submerged fermentation (SmF) using A. nidulans LCJ249 and A. flavus LCJ253. Among the six media tested, Medium 6 was found to be the best medium for maximum protease production in both A. nidulans LCJ249 (1178.0 U/mL) and A. flavus LCJ253 (950.6 U/mL). Effect of essential nutrient parameters like carbon, nitrogen and casein and other culture conditions such as incubation time, inoculum size, pH and shaking and static conditions were evaluated by the conventional one factor at a time approach. In the case of A. nidulans LCJ249, a medium containing 20 g/L glucose, 15 g/L malt extract, 5 g/L casein, initial medium pH of 7 and inoculum size of 30 mg/L favoured maximum protease production. Similarly, in A. flavus LCJ253, a medium containing 20 g/L starch, 20 g/L peptone, 15 g/L casein, initial medium pH of 7 and inoculum size of 10 mg/L favoured maximum protease production. In both the cultures, protease production was higher under shaking condition than in static conditions. The study showed that the optimised medium with optimal conditions enhanced protease production when compared to the original medium.

This study describes the isolation of actinomycetes, screening for their potential to produce industrially important enzymes and their molecular characterization. Twenty-five actinomycete strains were isolated from the soil samples of Pichavaram mangroves and were morphologically characterized. The isolates were screened for enzymes: L-asparaginase, lipase cellulase, amylase and protease. Five Streptomyces sp. showed a positive activity for all the enzymes studied. The isolates were further screened by quantitative method. The five Streptomyces spp. were further identified by conventional and molecular methods. Based on the molecular characterization, the novel isolates were identified as Streptomyces sp. LCJ10A (Accession no. KU 860466), Streptomyces sp. LCJ11A (Accession no. KU921107), Streptomyces sp. LCJ13A (Accession no. KU921109), Streptomyces sp. LCJ14A (Accession no. KU921110) and Streptomyces sp. LCJ16A (Accession no. KU 921112). These cultures showed good enzyme activity under submerged fermentation and therefore, they can be used in developing a low cost technology for industrial applications

Protease is an industrially important enzyme obtained from plants and animals. Production of high amounts of protease at low cost is necessary for its use in different commercial applications. The main objective of this work was to formulate a suitable medium and to optimize various parameters for protease production by Streptomyces sp. LCJ1A which was isolated from Pichavaram mangroves, Tamil Nadu, India. The organism was quantitatively and qualitatively screened for protease production.   Sequencing of 16S rRNA was done and the sequence was deposited in NCBI and Accession no. KU 870428 was obtained. For optimization, the conventional one-time factor method followed  by  the  Plackett-Burman  design  was  used  to  optimize  various  media components.  Variables  with  a  significant  influence  on  the production of protease have been identified. Variables such as maltose, peptone, pH and temperature have shown its strong impact on protease production and the ideal concentration of these factors was further investigated by Response Surface Methodology. The Optimum values of tested variables for favourable protease production were: Maltose, peptone, pH and temperature. Further, the interaction effects of maltose and peptone were found to be extremely important suggesting that both components were extremely crucial for protease production. 186.92 U/mL of protease enzyme was obtained in the experimental study which was close to the predicted value of 190.67 U/mL, which could validate the model. Using such optimized variables, the protease production was increased by 10 times when compared with the unoptimized medium. This is the first report on the conventional and statistical optimization of protease production from Streptomyces sp. LCJ1A. This study also showed that statistical methods are indeed a better approach for optimization of media, when compared with conventional one- factor-at-a-time method in terms of an enhanced protease yield in a short time