Microscope Assisted Uni-algal isolation through Dilution (MAU-D): a simple modified technique for tapping diverse cyanobacteria

Cyanobacteria are oxygenic photosynthetic microorganisms known for their agricultural and industrial importance. Unavailability of efficient and fast isolation and purification methods of cyanobacteria has impeded our understanding of cyanobacterial diversity. A number of techniques for isolation and purification of cyanobacteria are available, but most of them are cumbersome as well as time-consuming. In the present study, we modified and validated a uni-algal isolation technique named as Microscope Assisted Uni-algal isolation through Dilution (MAU-D) which used dilution of mixed algal population on slide and isolation of single type of cyanobacterial cells using light microscope. Using this technique, we obtained 81 cyanobacterial isolates belonging to various species from 19 different genera from soil and water samples collected from rice fields of Uttar Pradesh, India. This technique also resulted in isolation of six distinct genera, viz., Cyanobacterium, Toxopsis, Desertifilum, Chroococcidiopsis, Halomicronema, and Alkalinema,which were previously not reported from rice fields of India. Hence, the MAU-D technique presents a simple, comparatively fast method of isolation and purification of cyanobacteria which can help to isolate those cyanobacteria which are difficult to isolate through routine sub-culturing.