Interference by pigment in the estimation of microalgal biomass concentration by optical density
Interference by pigment in the estimation of microalgal biomass concentration by optical density
复制标题
DOI：
10.1016/j.mimet.2011.02.005
复制
发表时间：
2011-05-01
影响因子：
2.2
通讯作者：
Harrison, Susan T. L.
中科院分区：
文献类型：
--
作者：
Griffiths, Melinda J.;Garcin, Clive;Harrison, Susan T. L.
光密度是微生物细胞悬浮液中生物量浓度的一种方便的间接测量方法。使用合适的标准曲线，悬浮液对光的吸光度可以与细胞密度直接相关。然而，当细胞的色素含量发生变化时，可能会引入不准确的信息。在所采用的培养条件下，普通小球藻的色素含量随年龄和培养条件的变化在干重的0.5%~5.5%之间变化。由于吸光度的变化，这导致了生物量在生长周期过程中的显著误差。使用在生长周期的单个时间点产生的标准曲线来根据光密度计算干重(DW)，导致整个生长周期相对于实际DW的平均相对误差在680 nm处在9%至18%之间，在750 nm处为5%至13%。用低色素条件下产生的标准曲线估计正常色素条件下的生物量时，生物量估计相对于实际干重的平均相对误差在680 nm处为52%，在750 nm处为25%。栅藻、螺旋藻和微绿球藻也得到了类似的结果。建议的最小化误差的策略包括选择使色素的吸光度最小化的波长，例如750 nm，其中叶绿素是主要的色素，并生成接近中间或整个生长周期的标准曲线。(C)2011爱思唯尔B.V.保留所有权利。
Optical density is used as a convenient indirect measurement of biomass concentration in microbial cell suspensions. Absorbance of light by a suspension can be related directly to cell density using a suitable standard curve. However, inaccuracies can be introduced when the pigment content of the cells changes. Under the culture conditions used, pigment content of the microalga Chlorella vulgaris varied between 0.5 and 5.5% of dry weight with age and culture conditions. This led to significant errors in biomass quantification over the course of a growth cycle, due to the change in absorbance. Using a standard curve generated at a single time point in the growth cycle to calculate dry weight (dw) from optical density led to average relative errors across the growth cycle, relative to actual dw, of between 9 and 18% at 680 nm and 5 and 13% at 750 nm. When a standard curve generated under low pigment conditions was used to estimate biomass under normal pigment conditions, average relative errors in biomass estimation relative to actual dw across the growth cycle were 52% at 680 nm and 25% at 750 nm. Similar results were found with Scenedesmus, Spirulina and Nannochloropsis. Suggested strategies to minimise error include selection of a wavelength that minimises absorbance by the pigment, e.g. 750 nm where chlorophyll is the dominant pigment, and generation of a standard curve towards the middle, or across the entire, growth cycle. (C) 2011 Elsevier B.V. All rights reserved.