Optimization of protease production by Streptomyces sp. A6 using statistical approach for reclamation of shellfish waste

Retracted: Production, biochemical characterization, and kinetic/thermodynamic study of novel serine protease from Aspergillus avenaceus URM 6706

"Production, biochemical characterization, and kinetic/thermodynamic study of novel serine protease from Aspergillus avenaceus URM 6706" (by da Silva A, et al.) Bio. Tech. Prog.; https://aiche.onlinelibrary.wiley.com/doi/10.1002/btpr.3091 The above listed article, from Biotechnology Progress, published online in Early View on October 16, 2020 in Wiley Online Library (http://wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal's Editor-in-Chief, John A. Morgan and Wiley Periodicals LLC. The retraction has been agreed because the article was not accepted for publication by the Journal and subsequently published in error as an Early View article. The editorial team of this journal takes full responsibility and apologizes for the technical error that resulted in this article appearing in Early View.

The Goldilocks Approach: A Review of Employing Design of Experiments in Prokaryotic Recombinant Protein Production

The production of high yields of soluble recombinant protein is one of the main objectives of protein biotechnology. Several factors, such as expression system, vector, host, media composition and induction conditions can influence recombinant protein yield. Identifying the most important factors for optimum protein expression may involve significant investment of time and considerable cost. To address this problem, statistical models such as Design of Experiments (DoE) have been used to optimise recombinant protein production. This review examines the application of DoE in the production of recombinant proteins in prokaryotic expression systems with specific emphasis on media composition and culture conditions. The review examines the most commonly used DoE screening and optimisation designs. It provides examples of DoE applied to optimisation of media and culture conditions.

Microbial alkaline proteases: Optimization of production parameters and their properties

Proteases are hydrolytic enzymes capable of degrading proteins into small peptides and amino acids. They account for nearly 60% of the total industrial enzyme market. Proteases are extensively exploited commercially, in food, pharmaceutical, leather and detergent industry. Given their potential use, there has been renewed interest in the discovery of proteases with novel properties and a constant thrust to optimize the enzyme production. This review summarizes a fraction of the enormous reports available on various aspects of alkaline proteases. Diverse sources for isolation of alkaline protease producing microorganisms are reported. The various nutritional and environmental parameters affecting the production of alkaline proteases in submerged and solid state fermentation are described. The enzymatic and physicochemical properties of alkaline proteases from several microorganisms are discussed which can help to identify enzymes with high activity and stability over extreme pH and temperature, so that they can be developed for industrial applications.

Non-edible Oil Cakes as a Novel Substrate for DPA Production and Augmenting Biocontrol Activity of Paecilomyces variotii

The present study investigated the use of waste non-edible oil cakes (Jatropha, Karanja, Neem, and Mahua) as a substrate for the growth of Paecilomyces variotii and dipicolinic acid (DPA) production. Previous researches proved the efficacy of DPA in suppressing certain pathogens that are deleterious to the plants in the rhizosphere. DPA production was statistical optimized by amending non-edible oil cakes in growing media as nitrogen and sugars (Dextrose, Glucose, and Lactose) as carbon source. Plackett-Burman design (PBD), indicated that Jatropha cake, Karanja cake, and Dextrose were the most significant components (p < 0.05) of the media and were further optimized using response surface methodology (RSM). Jatropha cake, Karanja cake, and Dextrose at the concentration of 12.5, 4.5, and 10 g/l, respectively, yielded 250 mg/l of DPA, which was 2.5 fold more than that obtained from basal medium. HPLC analysis of the optimized medium (peak at retention time of 30 min) confirmed the enhanced DPA production by P. variotii. The scanning electron microscopy (SEM) images showed that optimized medium impose a stress like condition (due to less C:N ratio) for the fungus and generated more spores as compared to the basal medium in which carbon source is easily available for the mycelial growth. The antimicrobial activity of the fungal extract was tested and found to be effective even at 10⁻² dilution after 72 h against two plant pathogens, Fusarium oxysporum and Verticillium dahlia. Statistical experimental design of this study and the use of non-edible oil cakes as a substrate offer an efficient and viable approach for DPA production by P. variotii.

Optimization of succinic acid fermentation with Actinobacillus succinogenes by response surface methodology (RSM)

Succinic acid is considered as an important platform chemical. Succinic acid fermentation with Actinobacillus succinogenes strain BE-1 was optimized by central composite design (CCD) using a response surface methodology (RSM). The optimized production of succinic acid was predicted and the interactive effects between glucose, yeast extract, and magnesium carbonate were investigated. As a result, a model for predicting the concentration of succinic acid production was developed. The accuracy of the model was confirmed by the analysis of variance (ANOVA), and the validity was further proved by verification experiments showing that percentage errors between actual and predicted values varied from 3.02% to 6.38%. In addition, it was observed that the interactive effect between yeast extract and magnesium carbonate was statistically significant. In conclusion, RSM is an effective and useful method for optimizing the medium components and investigating the interactive effects, and can provide valuable information for succinic acid scale-up fermentation using A. succinogenes strain BE-1.

Fermentation medium for collagenase production by Penicillium aurantiogriseum URM4622

Medium composition and culture conditions for maximal collagenase production by Penicillium aurantiogriseum URM4622 were optimized using a response surface approach. A full two-level design on three factors (initial medium pH, soybean flour concentration, and temperature) was employed to identify the most significant fermentation parameters for collagenase production, and a subsequent central composite design (CCD) was used to find the optimal levels of the two most significant factors (initial medium pH and soybean flour concentration). The design results indicated that the initial medium pH and the temperature had significant negative main effects, whereas the substrate concentration had a positive effect on the collagenase production. The maximum collagenolytic activity predicted by the fitted response surface was expected to occur at pH 7.21, 1.645% soybean flour concentration and 24°C. Three replicate experiments were run at these conditions and yielded an activity response of 283.36 ± 1.33 U, which not only is the highest obtained in this study but also represents a 5-fold increase over the lowest response observed in the initial design. Since all experiments were carried out with an inexpensive substrate, the final results point out to a cost-effective medium for collagenase production with potential industrial-scale applications.