title: Medium optimization by response surface methodology for poly-gamma-glutamic acid production using dairy manure as the basis of a solid substrate.
abstract: Dairy manure, supplemented with agro-industrial materials, was used as the solid substrate for high yield of poly-gamma-glutamic acid (gamma-PGA) by Bacillus subtilis CCTCC202048. The solid-state fermentation medium was optimized by response surface methodology. In the first optimization step, a Plackett-Burman design was used to evaluate the influence of related factors. Wheat bran, soybean cake and glutamic acid were found to be more compatible supplement with dairy manure and positively influenced on gamma-PGA production. In the second step, the concentrations of the three supplemental nutrients above were further optimized using a Box-Behnken design. The average gamma-PGA yield (4.70%) in triplicate under optimal conditions was obtained on the laboratory scale, whereas it was 3.58% at compost experiment. These would lay a foundation for lessening the pollution of dairy manure, increasing fertilizer efficiency and exploring a late-model organic fertilizer that retains water and nutrients.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, National Engineering Research Centre of Microbial Pesticides, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Chen
authors.initials: C
authors.lastname: Xiong
authors.forename: Chen
authors.initials: C
authors.lastname: Shouwen
authors.forename: Sun
authors.initials: S
authors.lastname: Ming
authors.forename: Yu
authors.initials: Y
authors.lastname: Ziniu
mesh_terms: D000818:Animals; D001412:Bacillus subtilis / Q000378:metabolism*; D001431:Bacteriological Techniques / Q000379:methods; D002417:Cattle; D015169:Colony Count, Microbial; D003470:Culture Media; D003612:Dairying; D005285:Fermentation; D007218:Industrial Microbiology / Q000379:methods; D008372:Manure; D011099:Polyglutamic Acid / Q000096:biosynthesis*; D013379:Substrate Specificity
chemical_list: D003470:Culture Media; D008372:Manure; D011099:Polyglutamic Acid