of microorganisms in the wastewater treatment plants pays a major role in the
treatment process. According to ( Gerardi, 2007), the archaebacteria
and eubacteria are considered the most
important microorganisms in a biological Wastewater treatment plants. The two
prokaryotes are commonly referred to as bacteria. Wastewater treatment roles
attributed to bacteria include biological
phosphorus removal, degradation of soluble CBOD, floc formation, and
nitrification, denitrification, methanogens and fermentative processes.
Zooglea Ramigera has
long been considered the typically activated sludge bacterium responsible for
the floc formation. It
is capable of producing cellular components that enable flocs to “stick”
together or agglutinate.
to (Unz, 2017), since its discovery, Zooglea ramigera has been identified primarily from the
characteristic tree-like Zooglea which are frequently observed in polluted environments.
However, determination of its taxonomic position has been complicated due to
insufficient data in its physiology, biochemical and nutritional data to
accurately characterize and distinguish its species.
The generic name Zooglea originates from the Greek language meaning the “living glue'” because of its ability to attract nutrients
from the water. Based on
this description this organism obtained its name. Initially the only recognized
species of the genus Zooglea, Zooglea ramigera.
This report, therefore, focuses on its morphological characteristics,
relation with other organisms and its significance in society or in a specific
ecosystem that is relevant in water technology.Morphological characteristics
Zoogloea ramigera are extremely
large, non-motile bacteria and can grow usually as “amorphous” clumps or
“fingered” like a tree as shown in figure (1). These bacteria are arranged in
sharply demarcated columns or fingers which protrude from clusters. Its cells are straight
to slightly curved rod-shaped and are nonspore forming bacteria (Dugan, Stoner, & Pickrum, 2006).
Figure 1:Rod-shaped Zooglea ramigera(Adapted
et al., 2006)
bacteria’s staining is Gram-negative(Friedman, Dugan, Pfister, & Remsen, 1968). They are Neisser
negative. (Neisser positive turns
purple, while Neisser negative turns yellow). With this feature they can be
differentiated from filamentous.
Zoogloea ramigera forms characteristic cell aggregates surrounded by gellatinous
matrices, the zoogloeal matrices. This matrix is composed of extracellular polymer strands
of polysaccharides(Friedman et al., 1968). The polysaccharide coating of Zoogleal bacteria is always high or
excessive, see figure (2) below.
Figure 2: Zooglea ramigera clusters Figure 3: Excessive polysaccharide coating of
Zooglea ramigera (www.EnvironmentalLeverage.com)
live freely in organically polluted fresh waters or waste water treatment , (Dugan
et al., 2006). Usually,
its environment is characterized by a high food to mass ratio where there are readily
bio-degradable soluble organic compounds such as wastewater. It can also can be
in selector systems such as activated sludge(Williams & de los Reyes, 2006).
Figure 2: Habitat of Zooglea ramigera’s (Dugan et al., 2006)
and composition of the zoogloeal matrix and consider it in relation to
metabolic activities of the Zoogloea
ramigera (Madigan M; Martinko J, eds. ,2005). It possesses an extremely
active oxidative metabolism in the natural habitat. They are aerobic and
ramigera 1-16-M was found to
Zoogloea ramigera has
been found to contain two stereospecific acetoacetyl CoA reductases; 1)NADP+-linked
with D-?-fi-hydroxybutyryl-CoA specific,2) NAD+-linked and L(+)-isomer specific(Saito, Fukui, Ikeda, Tanaka, & Tomita, 2000). The NADP +-linked
enzyme has a pH optimum for the reduction of acetoacetyl CoA at PH of 8.1, however
for the oxidation of hydroxybutyryl –CoA, optimum PH is non -definite.
is not choosy nutritionally, thus a variety of organic carbon sources in a
simple defined media may be used to culture it (Gerardi, 2007).Poly-?-hydroxybutyrate
(PHB) is produced whenever both a carbon source is highly present as well as
B-ketothiolase. PHB synthesis and intracellular degradation is partially
controlled by NADPH and availability through glucose 6-phosphate dehydrogenase enzyme
with optimum operating PH of 8.5 .The species is also known to use Mn-oxidation
metabolism because the matrix made by Zoogloea takes in and concentrated metal
in water sources.Range for
pH, temperature, salt concentration
The preferred temperature for growth is 28-37
degrees C. Zooglea ramigera flourish
in an environment with a PH of 7.0-7.5. The formation of flocs and films in
liquid media at late stages of growth are distinguished by treelike or
fingerlike morphology. Colonies on C4 agar, at 3-4 days, reach 1mm in diameter
are circular, raised, & translucent with opaque centers of gray or white.
Mature colonies are tenacious and cohesive and can be lifted from agar surface
intact with a needle.
Control of the environment for Zooglea ramigera can be achieved via
PH and temperature. Similar to its
metabolic activities, the preferred temperature for growth is 28-37 degrees. Zooglea ramigera flourish in an
environment with a PH of 7.0-7.5 because a decrease in PH of the activated
sludge process favors the proliferation of filamentous fungi and disfavors the
growth of bacteria(Angelbeck
& Kirsch, 1969).
Nutrient type, addition, and
control is usually recommended. Zoogleal bulking occurs when the bacteria takes
too long to access nutrients in an environment with high BOD loading or
nutrient slug feeding rate is not consistent or when the nutrient is not
& Ph, 2003)) conditions that favor Zooglea or
other microbes responsible for viscous bulking are: High levels of soluble organics in the
influent and imbalance in macronutrient (C:N:P) favoring organisms that an uptake scarce
nutrients such as Zooglea ramigera.