Factors affecting accumulation and degradation of curdlan, trehalose and glycogen in cultures of Cellulomonas flavigena strain KU (ATCC 53703)

Abstract

Cellulomonas flavigena strain KU (ATCC 53703) is a cellulolytic, Gram-positive bacterium which produces large quantities of an insoluble exopolysaccharide (EPS) when grown in minimal media with a high carbon-to-nitrogen (C/N) ratio. Earlier studies proved the EPS is structurally identical to the linear β-1,3-glucan known as curdlan and provided evidence that the EPS functions as a carbon and energy reserve compound. We now report that C. flavigena KU also accumulates two intracellular, glucose-storage carbohydrates under conditions of carbon and energy excess. These carbohydrates were partially purified and identified as the disaccharide trehalose and a glycogen/amylopectin-type polysaccharide. A novel method is described for the sequential fractionation and quantitative determination of all three carbohydrates from culture samples. This fractionation protocol was used to examine the effects of C/N ratio and osmolarity on the accumulation of cellular carbohydrates in batch culture. Increasing the C/N of the growth medium caused a significant accumulation of curdlan and glycogen but had a relatively minor effect on accumulation of trehalose. In contrast, trehalose levels increased in response to increasing osmolarity, while curdlan levels declined and glycogen levels were generally unaffected. During starvation for an exogenous source of carbon and energy, only curdlan and glycogen showed substantial degradation within the first 24 h. These results support the conclusion that extracellular curdlan and intracellular glycogen can both serve as short-term reserve compounds for C. flavigena KU and that trehalose appears to accumulate as a compatible solute in response to osmotic stress.

The Genome Sequences of Cellulomonas fimi and “Cellvibrio gilvus” Reveal the Cellulolytic Strategies of Two Facultative Anaerobes, Transfer of “Cellvibrio gilvus” to the Genus Cellulomonas, and Proposal of Cellulomonas gilvus sp. nov

“…Curdlan, along with glycogen and trehalose have also been proposed as storage polysaccharides in C. flavigena [46]. All three organisms have 11 GH 13 family members that are intracellular and likely involved in glycogen synthesis, remodeling and degradation, or trehalose biosynthesis and degradation similar to that reported for C. flavigena [46]. The enzymes involved in curdlan synthesis are in the GT2 glycosyl transferase family but this family also functions in the synthesis of other oligosaccharides [47].…”

Reversible control of biofilm formation by Cellulomonas spp. in response to nitrogen availability

“…High C : N ratios have already been linked to the production of curdlan [β(1–3) glucan] capsules in Cellulomonas spp. (Voepel and Buller, 1990; Siriwardana et al ., 2011). Thus, we investigated if the biofilms were sequestering excess C as curdlan.…”

“…The formation of a curdlan capsule in Cellulomonas spp. was first reported in cultures of C. flavigena KU during entry in stationary phase (Buller and Voepel, 1990; Voepel and Buller, 1990) and later studies (Kenyon et al ., 2005; Siriwardana et al ., 2011) supported the notion that curdlan production is a general response of Cellulomonas spp. to high C : N ratios that leads to cell aggregation.…”

“…Curdlan capsules function as short‐term C reserve compounds in C. flavigena KU during stationary phase (Voepel and Buller, 1990; Siriwardana et al ., 2011). Similarly, the curdlan biofilm matrix served as a C source to support biofilm dispersal upon N supplementation (Fig.…”

Architecture, Function, Regulation, and Evolution of α-Glucans Metabolic Enzymes in Prokaryotes

“…β-Glucans can play other functions, including (i) cellulose as a fibrous structural component of bacterial biofilms, it forms a mechanically strong hydrogel with high water adsorption capabilities, 54 (ii) cyclic β-glucans act as messengers in plantmicrobe interactions, 55 (iii) internal and external energy storages. 56 The fungal cell wall is composed of a polysaccharide-based three-dimensional network that is continuously adapting to growth and environmental conditions and is essential for cell survival (1). The central core consists of a branched β(1→3)-glucan with 3% to 4% interchain linked (via β(1→4)-linkage) to chitin.…”