A Laboratory Case Study of Efficient Polyhydoxyalkonates Production by Bacillus cereus, a Contaminant in Saccharophagus degradans ATCC 43961 in Minimal Sea Salt Media

Abstract

A contaminating bacterium growing along with the stock culture of Saccharophagus degradans ATCC 43961 (Sde 2-40) on marine agar plate was isolated and investigated for its ability to produce polyhydoxyalkonates (PHA). Preliminary screening by Sudan black B and Nile blue A staining indicated positive characteristic of the isolate to produce PHA. The isolate was able to grow and produce PHA in minimal sea salt medium broth. PHA quantification studies with gas chromatographic analyses of the dry cells derived from culture broths revealed accumulation of PHA in bacterial cells. PHA production started after 20 h and increased with cell growth and attained maximum values of 61 % of dry cell weight at 70 h of cultivation. After 70 h, a slight decrease in the level of PHA content was observed. The nature/type of PHA was found to be poly(3-hydroxybutyraye) by Fourier transform-infrared spectroscopy. Microbiological and 16S rRNA gene sequencing analyses suggested that the PHA producing bacterial isolate belongs to Bacillus genera and shows 100 % nucleotide sequence similarity with Bacillus cereus species in GenBank. This study is a first report for ability of Bacillus species to grow in marine sea salt media and produce PHA. The media used for the polymer production was novel in the context of the genus Bacillus and the production of PHA was three-fold higher than Sde 2-40 using same growth medium. This study shows that the contaminant bacteria once properly investigated can be used for advantageous characteristic of metabolites production in place of original cultures.

Enhanced Agarose and Xylan Degradation for Production of Polyhydroxyalkanoates by Co-Culture of Marine Bacterium, Saccharophagus degradans and Its Contaminant, Bacillus cereus

“…The growth of B. cereus appeared after overnight incubation but Sde 2-40 was not visible until 20 h of incubation at 30 • C. However, Sde 2-40 colonies appeared on agar plate after 20 h of incubation and rapid increase in agar degradation on plates could be observed as the time progressed ( Figure 2B). Sde 2-40 grown alone produced eumelanin and started to die after three to four days of incubation, as observed in earlier reports [3,34]. However, the colony growth and pit size due to agar degradation by Sde 2-40 increased in the presence of B. cereus and eumelanin was not produced even after ten days of incubation.…”

“…The bottom organic phase was used for analysis. The detailed GC operating conditions are shown in a previous report [34].…”

“…Therefore, a strategy coupling steps of hydrolysis and fermentation (i.e., consolidated bioprocessing) is a smart approach to produce PHAs using carbon sources derived from algae and plants ( Figure 1A). In our previous study, we observed that Bacillus cereus (KF801505) grows as a contaminant along with Sde 2-40 cultures on sea salt minimal media and produces high amounts of PHAs [34]. We observed that the viability as well as agar degradation capability of Sde 2-40 increases while growing with B. cereus in agar plate cultures.…”

Comparative study of MnO2 nanoparticle synthesis by marine bacterium Saccharophagus degradans and yeast Saccharomyces cerevisiae

“…In this study, we observed a MnO 2 NP-specific peak at 365 nm for a lower concentration. Sde 2-40 is reported to produce metabolites like acetic acid (Taylor et al 2006;González-García et al 2011), cellulases (Taylor et al 2006;Jung et al 2014), and PHA (Sawant et al 2014;Salunke et al 2014a). Individual tests with cellulases (Celluclast 1.5 L and Viscozyme L as representatives) showed positive reactions, but washed Sde 2-40 cells, the supernatant of washed Sde 2-40 cells, washed sonicated cells, acetic acid, and PHA showed an inability to synthesize MnO 2 NPs.…”

Degradation of corn stover by fungal cellulase cocktail for production of polyhydroxyalkanoates by moderate halophile Paracoccus sp. LL1

“…PHAs are a class of polyesters natively produced by various microorganisms as a carbon reservoir during growth under stress conditions (Sawant et al, 2014). As PHAs have combined features of good biodegradability and comparable mechanical properties to those of petroleum-derived thermoplastics, they are considered as potential substitutes for conventional petrochemical plastics (Sawant et al, 2014).…”