Nutrisi Mikrobia

Nutrisi Mikrobia: Tipe nutrisi mikrobia

Berdasarkan sumber karbon:

• Heterotrof: organik, e.g. glukosa 
• Autotrof: anorganik, e.g. CO2

Berdasarkan sumber Energi:

• Fototrof: cahaya, e.g. cahaya matahari 
• Khemotrof: reaksi kimiawi,e.g. biooksidasi-reduksi (org & anorg)

Berdasarkan sumber donor elektron:

• Litotrof: anorganik e.g. H2O, H2S
• Organotrof: organik, e.g. glukosa

Nutrisi Mikrobia: Tipe nutrisi mikrobia

1. Foto-litotrofik autotrof :

• Sianobakteria: Oscilatoria, Nostoc,Anabaena 
• Algae: Euglena, Chlamydomonas, Volvox 
• Purple sulphur bacteria: Ectothiorhodospira 
• Green sulphur bacteria: Chlorobium Chloronema

2. Foto-organotrofik heterotrof:

• Purple non-sulphur bacteria: Rhodospirilum, Rhodopseudomonas 
• Green non-sulphur bacteria: Chloroflexus, Thermomicrobium 

3. Khemo-litotrofik autotrof:

• Sulphur oxidizing bacteria: Thiobacillus, Beggiatoa, Thiotrix 
• Hydrogen bacteria: Ralstonia, Alcaligenes 
• Nitrifying bacteria: Nitrosomonas, Nitrobacter, Nitrococcus 
• Iron oxidizing bacteria: Thiobacilus, Gallionella 

4.Khemo-organotrofik heterotrof:

• Non-fotosynthetic bacteria: Escherichia, Bacillus, Salmonella 
• Archaea: Methanococcus, Halococcus 
• Protozoa: Amoeba, Trypanosoma, Plasmodium 
• Fungi: Penicillium, Rhizopus, Mucor, Aspergillus, Saccharomyces 
• Slime molds: Physarum 
• Water molds: Pytophthora 

Uptake of nutrients

Nutrient molecules frequently cannot cross selectively permeable plasma membranes through passive diffusion and must be transported by one of three major mechanisms involving the use of membrane carrier proteins.

Transport via membran

Membran transport

Transportasi Nutrien

1. Passive diffusion 
2. Transport protein (uniport, simport, antiport) 
3. Facilitated diffusion 
4. Active transport 
5. Group translocation 
6. Chelating transport

1. Phagocytosis – Protozoa

2. Permeability absorption – Most microorganisms

• Passive transport simple diffusion 

• Facilitated diffusion

• Active transport 

• Group translocation

Passive diffusion

Passive diffusion is the process in which molecules move from a region of higher concentration to one of lower concentration as a result of random thermal agitation. A few substances, such as glycerol, can cross the plasma membrane by passive diffusion.

Difusi & osmosis

Facilitated diffusion

The rate of diffusion across selectively permeable membranes is greatly increased by the use of carrier proteins, sometimes called permeases, which are embedded in the plasma membrane. Since the diffusion process is aided by a carrier, it is called facilitated diffusion. The rate of facilitated diffusion increases with the concentration gradient much more rapidly and at lower concentrations of the diffusing molecule than that of passive diffusion.

A model of facilitated diffusion

The membrane carrier can change conformation after binding an external molecule and subsequently release the molecule on the cell interior. It then returns to the outward oriented position and is ready to bind another solute molecule. 

Because there is no energy input, molecules will continue to enter only as long as their concentration is greater on the outside.

Artikel / File ini diadopsi dari Drs. Langkah Sembiring, M.Sc., Ph.D. Fakultas Biologi UGM