UCA,_B4_1: First Blog Post

Nutrient data:

·         Mud: 30g

·         Cellulose: 0’5g

·         Sugar (glucose): 0’5g

·         Iron (II) sulphate (FeSO₄): 0’1g

·         Agar: 0’11g

·         Calcium carbonate: 0’5g

·         Sodium chloride: 0’54g

·         Water

In this research, we pretended to observe how well microorganisms evolved and how were they able to develop in an environment rich in some nutrients, such as glucose, cellulose and other metabolites, and how did they compete with other bacteria of the surroundings to reach those substances. Microorganism have been able, since the beginning of live on earth, to intelligently survive in a poor-oxygen-atmosphere earth, in which O₂ concentrations were very poor in contrast to carbon dioxide concentration. Some other inorganic molecules existed in that atmosphere, such as methane and nitrogen. In addition to this, high temperatures and radiation index indicated a very different atmosphere to the present-day atmosphere, so only some microorganisms could use those limited resources to correctly develop its metabolism. It is unbelievable how did those primitive bacteria and unicellular algae managed to survive in those conditions and, thereby, guaranteed the perpetuation of that cellular lineage throughout times. Therefore, we can make grow, practically, any kind of microorganism as long as we provide them their requirements. In the end, this is the objective of our investigation: study how can microorganisms develop in a limited space with limited food and oxygen.

Winogradsky column provided us a way to study how could the mud bacteria develop in an environment with nutrient concentration very different to natural mud: we added approximately 60 grams of silt in a column closed in one of his extremes, and opened to the atmosphere on the other. In normal conditions, we cannot distinguish any microorganism layer in mud, as it viscosity keeps it homogenous. However, in a Winogradsky column it is immobile, and its bottom has a poor oxygen concentration, so we can study several kinds of metabolism (aerobic and anaerobic). In addition, we added a few number of metabolites to see if some bacteria of the mud could break them down. Those metabolites are the following:

·         Sodium Chloride: Some bacteria can break down NaCl into its individual ions (chloride and sodium). This kind of bacteria is known as halobacteria (also called halobacteriacea), and can be found in waters with high salt concentration. It is included in archaea domain, rather than bacteria. Is also included in halophile community, as they need the presence of salt to grow and develop.

·         Cellulose:  Cellulose demotion is carried out by cellulolytic microorganisms. There are a lot of microorganisms capable of metabolizing cellulose, so we can’t just say that they are all aerobic or anaerobic. However, we’ll clasify them in groups and name a few examples. Anaerobic bacterias, for example, are the bacteroides like the bacteroides cellulolyticus, the acetivibrio cellulolyticus, clostridium thermocellum and ruminococcus like the ruminococcus flavefaciens. Anaerobic fungi are the piromonas communis and the sphaeromonas communis. Aerobic bacteria are genera like the cellulomonas or the cellvibrio. And anaerobic fungi are, for example, Trichoderma like the viride, reesei and koningii, penicillium pinophilum, and fusarium solani.

·         Glucose: Almost all organisms are capable of metabolizing glucose, so many that glycolysis is considered an almost universal process. We can’t identify the metabolism of a microorganism based only in the fact that they can metabolize glucose.

·         Iron sulphur: FeSO₄ is used by sulfate-reducing bacteria in anaerobic respiration, reducing the SO₄^2- to H₂S, which can often react with metal ions to produce metal sulfides like FeS, which are insoluble and dark, like brown or black. Some orders that include mostly sulfate-reducing bacteria are the desulfobacterales and the desulfovibrionales. Some genera that include only sulfate-reducing bacteria are the desulfotomaculum and the desulfosporosinus.

·         Agar: Despite agar is universally used as a farming environment, as it provides consistency and food to bacteria, it can be broken down by a special kind of microorganism: agarolytic bacteria. They live in seas and oceans, and can feed with algae agar. We pretended to study if some bacteria could demote agar while we offered consistency to the mud. Cytophaga psychrophila is an agarolytic bacteria.

·         Calcium carbonate: We added CaCO₃ to provide a carbon source. Its breakdown produces carbon dioxide (CO₂) and lime (CaO), a white substance.