THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

A newly isolated bacterium identified as Bacillus safensis based on biochemical tests and 16S rRNA analysis and its mutant variant created by exposure to ultraviolet radiation at 254 nm were investigated for keratinolytic activity. The wild-type strain produced 35.4–50.4 U/mL keratinase over a period of 120 h, while the mutant one yielded 64.4–108.5 U/mL keratinase for the same period of 120 h. The optimal conditions for the enzyme activities were pH 7.5 and 40 °C. The mutant and wild-type strain keratinases retained 59% and 54% of their activity after 12 h pretreatment at 40 °C, and 64% and 60% of their activity after 12 h at pH 7.5, respectively. The keratinases showed high substrate specificity for feathers, but low specificity for human and bovine hairs. The enzymes were activated by Na+, Ca2+, Fe2+ and Mg2+. However, while Mn2+ activated the enzyme from the mutant strain, it inhibited that of the wild type. The mutant and wild-type strain completely degraded whole chicken feathers after 6 and 9 days ...

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Bacillus safensis LAU 13: a new source of keratinase and its multi-functional biocatalytic applications

The study was conducted to select the best promising keratinolytic bacterial strain. A good keratinase positive bacterium isolated from the soil samples of Hazaribagh tannery industrial zone, Dhaka was identified as Arthrobacter genus depending on the conventional techniques and confirmed as Arthrobacter sp. by sequencing 16S rRNA gene. The medium components and culture conditions were optimized to enhance keratinase production through shake flask culture. Keratin and feather powder (10 g/l or 1%) were good substrates for the highest keratinase production along with yeast extract (0.2 g/l or 0.02%) as an organic nitrogen source and potassium nitrate (1 g or 0.1%) as an inorganic nitrogen source. Maximum yield of keratinase was found after 24 h of incubation at 37 °C with an initial pH of 7.0 and inoculums volume 5% under 150 rpm when keratin, yeast extract and potassium nitrate were used as nutrient sources. Keratinase production was more than 5.0-fold increased when all optimized parameters were applied simultaneously. The optimum reaction temperature and pH were determined to be 40 °C and 8.0 respectively for crude keratinase activity. Therefore, Arthrobacter sp. NFH5 might be used for large scale production of keratinase for industrial purposes in less time.

https://link.springer.com/content/pdf/10.1186%2Fs13568-017-0462-6.pdf

Production, partial optimization and characterization of keratinase enzyme by Arthrobacter sp. NFH5 isolated from soil samples

Bacillus subtilis 8 is highly efficient at degrading feather keratin. We observed integrated feather degradation over the course of 48 h in basic culture medium while studying the entire process with scanning electron microscopy. Large amounts of ammonia, sulfite, and L-cysteic acid were detected in the fermented liquid. In addition, four enzymes (gamma-glutamyltranspeptidase, peptidase T, serine protease, and cystathionine gamma-synthase) were identified that play an important role in this degradation pathway, all of which were verified with molecular cloning and prokaryotic expression. To the best of our knowledge, this report is the first to demonstrate that cystathionine gamma-synthase secreted by B. subtilis 8 is involved in the decomposition of feather keratin. This study provides new data characterizing the molecular mechanism of feather degradation by bacteria, as well as potential guidance for future industrial utilization of waste keratin.

Biodegradation of Feather Waste Keratin by the Keratin-Degrading Strain Bacillus subtilis 8.

Massive production of keratinaceous byproducts in the form of agricultural and industrial wastes throughout the world necessitates its justified utilization. Chemical treatment of keratin waste is proclaimed as an eco-destructive approach by various researchers since it generates secondary pollutants. Microbial degradation of keratin waste is an emerging and eco-friendly approach and offers dual benefits, i.e., treatment of recalcitrant pollutant (keratin) and procurement of a commercially important enzyme (keratinase). This review summarizes the potential utility of some bacterial and fungal species for the production of keratinase using a variety of keratinaceous wastes as growth substrates. The application of microbial keratinases in waste management; animal feed, detergent, and fertilizer manufacturing; and leather, cosmetic, and pharmaceutical industries is also abridged in this review.

Microbial production and industrial applications of keratinases: an overview

The aim of this study was to identify and optimize significant technological parameters influencing keratinolytic enzyme production by A. fradiae 119 and to study its ability to degrade keratin. In the present work chicken feathers meal (CFM) was found to be an excellent substrate for keratinase induction by A. fradiae 119. The strain produced 164 KU/mL keratinolytic activity in basal medium containing 7.5 g/L CFM as the sole source of carbon and nitrogen. Increased keratinolytic activity was achieved in media with ammonium sulfate as nitrogen source, the application of additional nitrogen sources to media containing CFM slightly decreased keratinase synthesis. Optimal parameters of the cultivation process were determined: pH of cultivation medium – 7.2, temperature – 34 oC and inoculum’s size – 8 %, using the response surface methodology. The yield of keratinase activity was increased by 46 % (267 KU/mL) after optimization of the cultivation process. The good ability of cultural liquid to degrade feathers and wool was detected.

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Optimization of keratinase production by actinomyces fradiae 119 and its application in degradation of keratin containing wastes

The aim was to develop a new improved Sorbent system (S-S) from organic sorbent material, nutrients, biosurfactant and microbial cell producing it for bioremediation of heavy oil hydrocarbons in various soil types. New sorbent material (S-M) was developed from paper mill short waste fibers because it requires very low energy to manufacture and the production costs of this S-M is extremely low compared to similar products in the market. S-M has good sorption characteristics for various oil products, is fully biodegradable, can be applied at sensitive environmental areas. S-M can be combined with microorganisms producing biosurfactant. The goal of investigations was to optimize S-S composition to minimize the leakage of heavy hydrocarbons to deeper soil layers or ground water. The optimal composition of S-S for all types of soil was determined: S-M 86.3-89.3%, microorganisms producing biosurfactant ≥ 107 CFU/g, biosurfactant solution – 3%, nutrients (nitrogen and phosphorous) 0.5 and 0.2%. Recommended optimal S-S moisture is 7%.

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O. Dižavičienė

Papers

Optimization of keratinase production by actinomyces fradiae 119 and its application in degradation of keratin containing wastes

Optimization Of Sorbent System From Paper Mill Waste Short Fibers For Bioremediation Of Heavy Hydrocarbons In Soil