Zulkeflee Zufarzaana, Aris Ahmad Zaharin, Shamsuddin Zulkifli H, Yusoff Mohd Kamil
Department of Environmental Sciences, Faculty of Environmental Studies, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
ScientificWorldJournal. 2012;2012:495659. doi: 10.1100/2012/495659. Epub 2012 Sep 10.
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.
一种产生生物絮凝剂的细菌菌株，其菌落形态特征为高度黏液状且呈丝状，被鉴定为芽孢杆菌属UPMB13，它被发现是一种潜在的生物絮凝剂产生菌。以高岭土作为悬浮颗粒，通过絮凝试验测定了阳离子依赖性、pH耐受性和剂量需求对该菌株絮凝能力的影响。絮凝活性通过光密度和絮凝物形成来测量。观察到单价和二价阳离子（即Na⁺、Ca²⁺和Mg²⁺）的添加具有协同作用，而Fe²⁺和Al³⁺对絮凝活性产生抑制作用。最终证明二价阳离子是增强絮凝的最佳阳离子来源。该生物絮凝剂在4.0至8.0的宽pH范围内起作用，其性能分别有显著差异（P < 0.05）。它在pH 5.0和pH 6.0时表现最佳，絮凝性能超过90%。过低或过高的pH都会抑制絮凝。阳离子和生物絮凝剂的剂量需求都很低，0.1%（w/v）的CaCl₂只需输入50 mL/L，培养液只需输入5 mL/L。这些结果与其他由各种微生物产生的、剂量需求更高的生物絮凝剂相当。
