Correlation between pellet morphology and glycopeptide antibiotic balhimycin production by Amycolatopsis balhimycina DSM 5908

Abstract

Actinomycetes, a class of filamentous bacteria, are an important source of several industrially relevant secondary metabolites. Several environmental factors including the media composition affect both biomass growth and product formation. Likewise, several studies have shown that environmental factors cause changes in cellular morphology. However, the relationship between morphology and product formation is not well understood. In this study, we first characterized the effect of varying concentrations of phosphate and ammonia in defined media on pellet morphology for an actinomycete Amycolatopsis balhimycina DSM 5908, which produces balhimycin, a glycopeptide antibiotic. Our results show that higher balhimycin productivity is correlated with the following morphological features: (1) higher pellet fraction in the biomass, (2) small elongated pellets, and (3) shorter filaments in hyphal growth in the periphery of the pellets. The correlation between morphology and product formation was also observed in industrially relevant complex media. Although balhimycin production starts after 72 h with maximum production around 168 h, the morphological changes in pellets are observed as early as 24 h after commencing of the batch. Therefore, morphology may be used as an early predictor of the end-of-batch productivity. We argue that a similar strategy can be developed for other strains where morphological indicators may be used as a batch monitoring tool.

Secondary Metabolite Production from Industrially Relevant Bacteria is Enhanced by Organic Nanofibers

“…The strong affinity for fibers might result from mutual electrostatic, hydrophobic interactions involving proteins forming the superficial layer of aerial hyphae. The density of the fibrous materials, related to the interconnected porosity of polymer nanofibers, which can reach values as high as 80–90%, also plays an important role, because it disfavors mycelia entanglements and formation of bacterial pellets, which cause suboptimal growth and production yields in SmF cultures (i.e., without solid substrates for cell adsorption) . In our samples, voids among fibers typically range around a few tens of μm, which well‐matches the size of pores (50–100 μm) requested for enhancing productivity .…”

Quantifying the branching frequency of virtual filamentous microbes using fractal analysis

“…The outcome of fermentation processes involving filamentous microbes depends heavily on the morphological form adopted by the organism, as this can have a significant influence on process productivity, both directly and indirectly (Papagianni, 2004; Wucherpfennig et al, 2010). Quantitative methods have been used in several studies to elicit relationships between morphology and productivity, but analysis is often restricted to the macroscopic level (Babič and Pavko, 2012; Driouch et al, 2012; Sitanggang et al, 2010), or an emphasis on morphological classification is often evident (Choy et al, 2011; Driouch et al, 2012; Posch et al, 2012; Singh et al, 2012). This classification requires that different parameters are used to quantify different morphological forms.…”

“…The optimization of fermentation processes involving filamentous microorganisms requires knowledge of the relationship between biomass and metabolite production. The morphological form adopted by an organism, which is dependent on a variety of factors (Wucherpfennig et al, 2010), is of critical importance, as particular phenotypes are associated with peak metabolite yield (Ahamed and Vermette, 2010; Babič and Pavko, 2012; Choy et al, 2011; Driouch et al, 2012; Singh et al, 2012; Sitanggang et al, 2010; Wucherpfennig et al, 2011). However, such associations are often restricted to the macroscopic level.…”

“…But, such metrics reveal little about underlying branching behavior. Furthermore, as different growth forms have necessitated the use of different parameters for morphological quantification, a considerable amount of effort has been expended in designing imaging systems capable of discriminating between these different phenotypes (Choy et al, 2011; Driouch et al, 2012; Papagianni and Mattey, 2006; Posch et al, 2012; Singh et al, 2012; Treskatis et al, 1997; Tucker et al, 1992). As different metrics are then applied to different “classes,” a comparison of the morphology of different classes is not possible.…”

Enhanced enzyme production with the pelleted form of D. squalens in laboratory bioreactors using added natural lignin inducer

“…Scale bar 10 mm Our results show that maximal productivity of a particular enzyme is found under the experimental conditions where maximal activity also occurs. There is a correlation between those two parameters and pellet growth, morphology and size, therefore controlling of pellet morphology and size by cultivation conditions can be used for optimal production of a particular enzyme [28]. Maximal Lac production was obtained in the STR with smaller, smooth and round pellets, while maximal MnP production occurred in the BCR with larger and smooth pellets.…”