Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411007, India.
Yeast. 2011 Oct;28(10):721-32. doi: 10.1002/yea.1901. Epub 2011 Sep 8.
Yarrowia lipolytica 3589, a tropical marine yeast, grew aerobically on a broad range of bromoalkanes varying in carbon chain length and differing in degree and position of bromide group. Amongst the bromoalkanes studied, viz. 2-bromopropane (2-BP), 1-bromobutane (1-BB), 1,5-dibromopentane (1,5-DBP) and 1-bromodecane (1-BD), the best utilized was 1-BD, with a maximal growth rate (μ(max) ) of 0.055 h⁻¹ and an affinity ratio (μ(max) /K(s) ) of 0.022. Utilization of these bromoalkanes as growth substrates was associated with a concomitant release of bromide (8202.9 µm) and cell mass (36 × 10⁹ cells/ml), occurring maximally on 1-BD. Adherence of yeast cells to these hydrophobic bromoalkanes was observed microscopically, with an increase in cell size and surface hydrophobicity. The maximal cell diameter was for 1-BD (4.66 µm), resulting in an increase in the calculated cell surface area (68.19 µm²) and sedimentation velocity (1.31 µm/s). Cell surface hydrophobicity values by microbial adhesion to solvents (MATS) analysis for yeasts grown on bromoalkanes and glucose were significantly high, i.e. >80%. Similarly, water contact angles also indicate that the cell surface of yeast cells grown in glucose possess a relatively more hydrophilic cell surface (θ = 49.1°), whereas cells grown in 1-BD possess a more hydrophobic cell surface (θ = 90.7°). No significant change in emulsification activity or surface tension was detected in the cell-free supernatant. Thus adherence to the bromoalkane droplets by an increase in cell size and surface hydrophobicity leading to debromination of the substrate might be the strategy employed in bromoalkane utilization and growth by Y. lipolytica 3589.
解脂耶氏酵母 3589 是一种热带海洋酵母，能够在碳链长度不同、溴代基团位置和程度不同的一系列溴代烷烃上进行有氧生长。在所研究的溴代烷烃中，最好的利用物是 1-溴代癸烷（1-BD），最大生长速率（μ(max) ）为 0.055 h⁻¹，亲和比（μ(max) /K(s) ）为 0.022。这些溴代烷烃作为生长基质的利用伴随着溴化物（8202.9 μmol）和细胞质量（36×10⁹ 个细胞/ml）的同时释放，在 1-BD 上最大。酵母细胞对这些疏水性溴代烷烃的附着可以通过显微镜观察到，细胞大小和表面疏水性增加。1-BD 的最大细胞直径为 4.66 μm，导致计算出的细胞表面积（68.19 μm²）和沉降速度（1.31 μm/s）增加。通过微生物对溶剂的粘附（MATS）分析，在溴代烷烃和葡萄糖上生长的酵母的细胞表面疏水性值显著较高，即>80%。同样，水接触角也表明，在葡萄糖中生长的酵母细胞的细胞表面具有相对更亲水的表面（θ=49.1°），而在 1-BD 中生长的细胞具有更疏水的细胞表面（θ=90.7°）。在无细胞上清液中未检测到乳化活性或表面张力的显著变化。因此，细胞大小和表面疏水性的增加导致底物脱溴可能是解脂耶氏酵母 3589 利用和生长溴代烷烃的策略。
