Cellulomonas

• Cellulomonas biazotea
• Cellulomonas bogoriensis
• Cellulomonas cartae
• Cellulomonas cellasea
• Cellulomonas cellulans
• Cellulomonas denverensis
• Cellulomonas fermentans
• Cellulomonas fimi
• Cellulomonas flavigena
• Cellulomonas gelida
• Cellulomonas hominis
• Cellulomonas hominilata
• Cellulomonas iranensis
• Cellulomonas persica
• Cellulomonas terrae
• Cellulomonas turbata
• Cellulomonas uda
• Cellulomonas xylanilytica

Cellulomonas is a genus of rod-shaped, aerobic or facultative anaerobic bacteria in the soil with a chemoorganotrophic metabolism ( Chemoorganotrophie ). They are catalase - positive, and be counted among the gram- positive bacteria, but are easy to discolor anyway. Cellulomonas cultures are mostly opaque, pigmented yellow and convex. The movement is performed by one or more flagella. The most important habitats are the soil and decomposed plant material. Optimal growth takes place at a temperature of 30 ° C and a pH of between 9 and 10.

Taxonomy

As early as 1923, the genus Cellulomonas by David H. Bergey et al. first reported as gram-negative bacteria. Later it has been found that they are gram - positive, but very easily decolorized. To date, 18 different species of this genus are known, of which Ce. flavigena represents the type species, which has the JGI (Joint Genome Institute ) sequenced completely. The genome contains 3785 genes. DNA-DNA hybridization studies and studies of the 16S ribosomal rRNA showed that the genus Oerskovia can be counted to Cellulomonas.

Metabolism

Cellulomonas have either an oxidative or fermentative metabolism. Most types produce both aerobically and anaerobically acid from glucose, maltose, sucrose, xylose and lactose. Cellulomonas is able to hydrolyze cellulose ( by cellulase ), starch and gelatin. Moreover, they reduce nitrate to nitrite and produce DNases.

Cellulose decomposition

Cellulose molecules are chains of glucose molecules. The basic unit is the disaccharide cellobiose. Cellulose is composed of the amorphous ( disordered ) and the crystalline (ordered ) field.

Cellulases decompose ( hydrolyze ) the bonds of cellobioses. They are associated with the cell surface of Cellulomonas, so that the soluble decomposition product may be rapidly absorbed. In order to obtain the largest possible surface reaction, the bacteria interfere with their longitudinal body axis parallel to the Cellulosefibrille.

There are two basic types of cellulases: An enzyme complex is firmly connected to the bacterium, while the other is free in the extracellular space. Cellulomonas flavigena applies both methods.

Cellulases form a whole enzyme family:

Cellobiose and glucose are added finally to the cell.

The absorbed disaccharides can be decomposed by the cellobiose still without ATP is required:

Hemicellulose decomposition

Hemicellulose is an alkali-soluble polysaccharide and consists of three main sugar components ( xylans, mannans, galactans ), and many side groups, such as acetyl, methyl, uronic acid. In contrast to cellulose, instead of β -D glucose Hexose pentose β -D-xylose, in which the C6 group is replaced by a hydrogen atom.

Hemicellulose is easily degradable and water-soluble as cellulose, as it provides a shorter chain, branched, and is not crystalline. The main constituent of xylans form, which can be degraded by xylanases. For the cleavage of the side groups other enzymes are needed. Main products of degradation are β -D - Xylolose and the disaccharide xylobiose.