Essay on Microbial Analysis of Soil

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Microbial analysis of soil, of top layer from selected sites of
Area near Dahisar River
Saika N. Esani
University of Mumbai (Email –

Abstract: soil samples were collected fortnightly from area near Dahisar River, A river in suburb of Mumbai. laboratory analysis started from July 2010 to September 2010. Total bacterial and fungal count were estimated by standard spread plate isolation. Isolated bacteria were subject to colony characterization and were estimated by their morphological and biochemical characters. As being a monsoon the occurrence of variation of different species were high. The microorganisms isolated from the soil were of staphylococcus strain and were gram positive, aerobic, coccus shaped
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Microbiological evaluation
Ten (10) grams of the soil sample for microbiological evaluation was weighed into 9ml of sterile water.
Preparation of serial dilution goes thus: 1ml of the original stocks solution was poured into 9ml sterile distilled water and mixed thoroughly to give 10-2 of the original sample and this was done for each sample and the bottles labeled according to date of collection
Isolation and Enumeration of Micro-organisms.
1gram of the samples was homogenized in 9mls of distilled water to obtain a ratio of 1:9 and the second diluted of each sample was plated using the pour plate technique.
Sterile molten nutrient agar (NA), potato dextrose agar (PDA), macconky’s agar,(MA) manitol salt agar (MSA) and deoxycholate astrate agar (DCA) were used{the potato dextrose agar (PDA) was acidified). These agars were then added and left to solidify undisturbed. These plates were incubated 37oC for 24hours (incubation was aerobic) and the procedure was repeated using 10-2 finally the number of colonies per plates were counted and recorded. The acidified PDA was incubated at 25C for 3-7 days for microbial growth. Total Bacterial counts (Cfu/g)
The total bacteria count for each sample was determined with the pour plate techniques using nutrient agar. The plates were incubated between 24hours at 370C and all colonies appearing on the end of the incubation period were counted using digital unlimited colony counter and the

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