title: Cation dependence, pH tolerance, and dosage requirement of a bioflocculant produced by Bacillus spp. UPMB13: flocculation performance optimization through kaolin assays.
abstract: A bioflocculant-producing bacterial strain with highly mucoid and ropy colony morphological characteristics identified as Bacillus spp. UPMB13 was found to be a potential bioflocculant-producing bacterium. The effect of cation dependency, pH tolerance and dosage requirement on flocculating ability of the strain was determined by flocculation assay with kaolin as the suspended particle. The flocculating activity was measured as optical density and by flocs formation. A synergistic effect was observed with the addition of monovalent and divalent cations, namely, Na⁺, Ca²⁺, and Mg²⁺, while Fe²⁺ and Al³⁺ produced inhibiting effects on flocculating activity. Divalent cations were conclusively demonstrated as the best cation source to enhance flocculation. The bioflocculant works in a wide pH range, from 4.0 to 8.0 with significantly different performances (P < 0.05), respectively. It best performs at pH 5.0 and pH 6.0 with flocculating performance of above 90%. A much lower or higher pH would inhibit flocculation. Low dosage requirements were needed for both the cation and bioflocculant, with only an input of 50 mL/L for 0.1% (w/v) CaCl₂ and 5 mL/L for culture broth, respectively. These results are comparable to other bioflocculants produced by various microorganisms with higher dosage requirements.
authors.affiliation: Department of Environmental Sciences, Faculty of Environmental Studies, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. zufar@env.upm.edu.my
authors.forename: Zufarzaana
authors.initials: Z
authors.lastname: Zulkeflee
authors.forename: Ahmad Zaharin
authors.initials: AZ
authors.lastname: Aris
authors.forename: Zulkifli H
authors.initials: ZH
authors.lastname: Shamsuddin
authors.forename: Mohd Kamil
authors.initials: MK
authors.lastname: Yusoff
mesh_terms: D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000737:chemistry; D001407:Bacillus / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D018407:Bacterial Physiological Phenomena; D061249:Batch Cell Culture Techniques / Q000379:methods / Q000592:standards*; D001688:Biological Products / Q000737:chemistry / Q000302:isolation & purification; D002122:Calcium Chloride / Q000737:chemistry; D002413:Cations, Divalent / Q000737:chemistry*; D002414:Cations, Monovalent / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D004357:Drug Synergism; D005296:Ferrous Compounds / Q000737:chemistry; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007616:Kaolin / Q000737:chemistry; D015636:Magnesium Chloride / Q000737:chemistry; D055620:Optical Phenomena; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D013045:Species Specificity
chemical_list: D017607:Aluminum Compounds; D001688:Biological Products; D002413:Cations, Divalent; D002414:Cations, Monovalent; D002712:Chlorides; D005296:Ferrous Compounds; D015636:Magnesium Chloride; D007616:Kaolin; C020748:ferrous sulfate; D000077410:Aluminum Chloride; D012965:Sodium Chloride; D002122:Calcium Chloride