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Water Sci Technol. 2014;70(2):200-8. doi: 10.2166/wst.2014.149.

Optimized culture condition for enhancing lytic performance of waste activated sludge by Geobacillus sp. G1.

Author information

1
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), P.O. Box 2614, 202 Haihe Road, Harbin 150090, China E-mail: waj0578@hit.edu.cn.
2
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), P.O. Box 2614, 202 Haihe Road, Harbin 150090, China E-mail: waj0578@hit.edu.cn; Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China.
3
Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China.

Abstract

Hydrolysis is known as the rate-limiting step during waste activated sludge (WAS) digestion. The optimization of the culture conditions of Geobacillus sp. G1 for enhancing WAS hydrolysis was conducted in this study with uniform design and response surface methodology. Taking the lysis rate of Escherichia coli as the response, the Plackett-Burman design was used to screen the most important variables. Experimental results showed that the maximum predicted lysis rate of E. coli was 50.9% for 4 h treatment time with concentrations of skim milk, NaCl and NH4SO4 at 10.78, 4.36 and 11.28 g/L, respectively. The optimized dosage ratio of Geobacillus sp. G1 to WAS was 35%:65% (VG1:VWAS). Under this condition, soluble protein was increased to 695 mg chemical oxygen demand (COD)/L, which was 5.0 times higher than that obtained in the control (140 mg COD/L). The corresponding protease activity reached 1.1 Eu/mL. Scanning electron microscopy showed that abundant cells were apparently lysed with treatment of Geobacillus sp. G1.

PMID:
25051465
DOI:
10.2166/wst.2014.149
[Indexed for MEDLINE]

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