title: High yield of poly-gamma-glutamic acid from Bacillus subtilis by solid-state fermentation using swine manure as the basis of a solid substrate.
abstract: Solid-state fermentations (SSF), using swine manure as the basis of a solid substrate, were carried out for high yield of poly-gamma-glutamic acid (gamma-PGA) by Bacillus subtilis CCTCC202048. Fermentation medium and process parameters were optimized through three orthogonal array designs. The optimal medium consisted of 62.3% (w/w, dry weight basis) swine manure, 25.0% soybean cake, 5.0% wheat bran, 5.0% glutamic acid, 2.5% citric acid and 0.2% MnSO4.H2O. The optimal process parameters were 15.0 g medium with initial moisture content 60% and initial pH 9.0 in 250 ml flask, inoculation at mid-log phase with a 4% inoculum level and cultivation for 48 h at 37 degrees C. The average-PGA yield (6.0%) in triplicate under optimal conditions was obtained on the laboratory scale while it was 4.5% at compost experiment. These would lay a foundation for lessening the pollution of swine manure, increasing fertilizer efficiency and exploring a late-model organic fertilizer that retains water and nutrients.
authors.affiliation: National Key Laboratory of Agricultural Microbiology, National Engineering Research Centre of Microbial Pesticides, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Xiong
authors.initials: X
authors.lastname: Chen
authors.forename: Shouwen
authors.initials: S
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
authors.forename: Ziniu
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000818:Animals; D001412:Bacillus subtilis / Q000378:metabolism*; D005285:Fermentation; D008372:Manure; D011099:Polyglutamic Acid / Q000096:biosynthesis*; D013552:Swine; D013997:Time Factors
chemical_list: D008372:Manure; D011099:Polyglutamic Acid