title: Production and characterization of a thermostable bioflocculant from Bacillus subtilis F9, isolated from wastewater sludge.
abstract: A bacterium isolated from wastewater sludge, identified as Bacillus subtilis F9, was confirmed to produce bioflocculant with excellent flocculation activity. The effects of culture conditions such as initial pH, temperature, carbon source, nitrogen source, and inoculum size on bioflocculant production were studied here. The results indicated that 2.32g/L of purified bioflocculant could be extracted with the following optimized conditions: 20gL(-1) sucrose as the carbon source, 3.5gL(-1) peptone as the nitrogen source, an initial pH of 7.0, and a temperature of 40°C. The purified bioflocculant consisted of 10.1% protein and 88.3% sugar, including 38.4% neutral sugar, 2.86% uronic acid, and 2.1% amino sugar. The neutral sugar consisted of sucrose, glucose, lactose, galactose, and mannose at a molar ratio of 2.7:4.7:3.2:9.1:0.8. Elemental analysis of the purified bioflocculant revealed that the weight fractions of carbon, hydrogen, oxygen, nitrogen, and sulfur were 30.8%, 5.3%, 54.7%, 6.4%, and 2.9%, respectively. Furthermore, the purified bioflocculant was pH tolerant within the range of 2-8 and thermotolerant from 10°C to 100°C, with optimal activity at pH 7.0 and at a temperature of 40°C. The purified bioflocculant showed industrial potential for the treatment of drinking water. Considering these properties, especially its low molecular weight (5.3×10(4)Da), this bioflocculant with excellent solubility and favorable flocculation activity is particularly suited for flocculating small particles.
authors.affiliation: Deptartment of Biotechnology, Periyar Maniammai University, Thanjavur 613403, Tamil Nadu, India; Lab of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea. Electronic address: ssgiri@snu.ac.kr.
authors.forename: Sib Sankar
authors.initials: SS
authors.lastname: Giri
authors.affiliation: Deptartment of Biotechnology, Periyar Maniammai University, Thanjavur 613403, Tamil Nadu, India; Department of Chemical Engineering, National Institute of Technology, Tiruchirapalli 620015, India. Electronic address: harshiny37@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Harshiny
authors.affiliation: School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address: shibsankar.iicb@gmail.com.
authors.forename: Shib Sankar
authors.initials: SS
authors.lastname: Sen
authors.affiliation: Deptartment of Biotechnology, Periyar Maniammai University, Thanjavur 613403, Tamil Nadu, India. Electronic address: drvsukumar@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Sukumaran
authors.affiliation: Lab of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea. Electronic address: parksec@snu.ac.kr.
authors.forename: Se Chang
authors.initials: SC
authors.lastname: Park
mesh_terms: D001412:Bacillus subtilis / Q000302:isolation & purification* / Q000378:metabolism; D002244:Carbon / Q000737:chemistry; D055598:Chemical Phenomena; D003470:Culture Media / Q000737:chemistry; D060766:Drinking Water / Q000737:chemistry; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009584:Nitrogen / Q000737:chemistry; D012722:Sewage / Q000382:microbiology*; D013395:Sucrose / Q000737:chemistry; D013696:Temperature
chemical_list: D003470:Culture Media; D060766:Drinking Water; D012722:Sewage; D013395:Sucrose; D002244:Carbon; D009584:Nitrogen
keywords: Bacillus subtilis; Bioflocclulant; Characterization; Polysaccharides; Wastewater sludge