CONCLUSION

The micropipette, capillary tube methods still lack in obtaining bacteria free cultures.  Although sophisticated instrumental techniques for the analysis and characterization are newer, often these experimental approaches will not replace traditional methods involving culturing, microscopy and extraction.  Similar to the variety in the isolation methods, culture media recipes are enormous. The advancement in the techniques over a century has   provided several advanced culture media with diverse composition. The evolution in the media lies in the addition of more nutrients which mimics the natural environment. Miquel’s (1892-93) recipe contained fewer amounts of nutrients but included all the important nutrients; it lacked the inclusion of the trace elements, vitamins and some of the macro nutrients mentioned in the complex media diatom artificial media (Figure 2).  The most “evolved” diatom culture media is important for growing various microalgae and also to understand the metal impact on the physiology (Gagneux-Moreaux et al., 2007).

Figure 2: The presence and absence of nutrients in the 19th century (Miquel, 1892-93) and 20th century media (Gagneux-Moreaux et al., 2007)