Detection and cultivation of filamentous bacteria from activated sludge

Abstract

Different applications of the activated sludge treatment process are employed globally for the biological treatment of wastewater. Since the activated sludge process was first developed, different kinds of sedimentation problems, in particular bulking sludge and foaming, have been observed and it is widely accepted that extensive, uncontrolled growth of filamentous bacteria is the main cause of these difficulties. Since the pioneering work of Eikelboom and coworkers who characterized and described seven groups of 26 morphological types of filamentous organisms several attempts have been made to develop new methods for isolation, cultivation and identification of the isolates. Improvement has also been sought in the methods for direct detection, to allow a better understanding of the complex phenomena of sludge bulking and foaming. However, although knowledge of the phylogeny of filamentous organisms has increased recently, only a few attempts have been made to achieve a better understanding of their growth characteristics. The aim of this paper is to give an overview of detection and cultivation methods with special emphasis on the comparison of classical approaches with the modern molecular biological methods, including in situ detection and identification of filamentous bacteria.

Linking Sequence to Function in Soil Bacteria: Sequence-Directed Isolation of Novel Bacteria Contributing to Soilborne Plant Disease Suppression

“…The suspension was vortexed (1 min), sonicated (1 min), vortexed again (15 s), serially diluted in SW, and spread plated in Leptothrix strain medium (LM; per liter, 5g peptone, 0.2 g magnesium sulfate heptahydrate, 0.15 g ferric ammonium citrate, 0.05 g calcium chloride, 0.01 g anhydrous ferric chloride, 0.01 g manganese sulfate monohydrate, 15 g agar [3]), yeast agar van Niel's (YAN; per liter, 10 g yeast extract, 1 g dipotassium phosphate, 0.5 g magnesium sulfate heptahydrate, 15 g agar [3]), buffered nutrient agar (NB; per liter, 4 g peptone, 4 g sodium chloride, 2 g yeast extract, 1 g beef extract, 0.45 g monopotassium phosphate, 1.78 g disodium hydrogen phosphate heptahydrate, 15 g agar [3]), and R2A (medium for growth of heterotrophic organisms; Difco BD). These culture media were previously reported to support the growth of various Burkholderiales species, including members of the Comamonadaceae and genera incertae sedis (R2A, NB, LM, and YAN) (3,29,35,49). Plates were incubated for 48 h at room temperature (RT) in the dark.…”

‘Morphological shifts’ in filamentous bacteria isolated from activated sludge processes

“…Numerous attempts to control bulking and foaming have been made, but they have not been successful, largely due to the failure to identify the causative organisms (Eikelboom 1975). Isolation of filamentous bacteria is a pre-requisite for the investigation of these organisms (Ka¨mpfer 1997). Pure culture studies have shown promise as an essential tool for studying filamentous bacteria on the basis of morphology, nutritional requirements and physiology.…”

“…Isolation of filamentous bacteria is an essential requirement for the investigation of biochemical and metabolic kinetics. However, systematic approaches to the nutritional requirements of different filamentous organisms are limited due to the difficulty of isolating them (Ka¨mpfer et al 1995;Ka¨mpfer 1997).…”

Characterization and experimental infection of Flexibacter maritimus (Wakabayashi et al. 1986) in hatcheries of post-larvae of Litopenaeus vannamei Boone, 1931

“…and Thiotrix sp.. It has also been reported that high bacterial infection rates cause necrosis and serious histological changes in gill tissues in shrimp larvae, affecting the respiratory system, and physiology as a whole (Kampfer, 1997;Amrane and Prigent, 1998).…”