title: Yeast screening from avermectins wastewater and investigation on the ability of its fermentation.
abstract: Wastewater from avermectin production is refractory with high output, high chemical oxygen demand (COD) concentration and high cost further. The current wastewater treatment technology, with little reuse of the organic material, needs high dilution ratio during treatment. Yeast single cell protein was produced from the wastewater of avermectins fermentation in this research. First, the yeast strain (H-1) which show enough tolerance to avermectins residue was screened from the wastewater, and it was identified as being most closely related to Candida tropicalis (100%, EF120592.1) using 18S rDNA gene sequence analysis. Second, its growth characteristics in the avermectins wastewater were studied. The dry biomass reached the maximal point of 10 g/L, the COD removal was up to 66.67%, and avermectins removal in the wastewater was 99.48% at the optimal condition that it was liquid volume 50 ml (250 ml flask), pH 4.0, temperature 30°C, inoculum volume 10% (V/V) and fermentation period 20 h. Third, the nutritional contents of dry yeast powder were determined, in which the water content was 8.12%, ash content was 5.18% and the crude protein was 40.02%. The dry yeast powder from avermectin waste liquor was promising to be used as a raw material or nitrogen source for commercial production of avermectins. The project was economically feasible by primary cost accounting.
authors.affiliation: College of Bioscience and Bioengineering, Hebei University of Science and Technology, Shijiazhuang, 050018, Hebei, People's Republic of China.
authors.forename: Xiao-Xiao
authors.initials: XX
authors.lastname: Wang
authors.forename: Zi-Hua
authors.initials: ZH
authors.lastname: Zhao
authors.forename: Tian-Shi
authors.initials: TS
authors.lastname: Chang
authors.forename: Jun-Guo
authors.initials: JG
authors.lastname: Liu
mesh_terms: D019149:Bioreactors; D041022:Candida tropicalis / Q000378:metabolism; D002241:Carbohydrates / Q000737:chemistry; D004275:DNA, Ribosomal / Q000378:metabolism; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000302:isolation & purification; D011208:Powders; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013302:Streptomyces / Q000378:metabolism; D013696:Temperature; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D002241:Carbohydrates; D004275:DNA, Ribosomal; D004364:Pharmaceutical Preparations; D011208:Powders; D014874:Water Pollutants, Chemical; D007559:Ivermectin; C019264:avermectin; D009584:Nitrogen