Project description:A continuous culture of Bifidobacterium longum NCC2705 was carried out in a 2.5-l reactor (Bioengineering AG, Wald, Switzerland), equipped with a Biospectra control system (Biospectra AG, Schlieren, Switzerland) and containing 2 l of MRS, added of 0.05% cysteine, inoculated with 2 % (v/v) preculture. The temperature was maintained at 37°C and the pH at 6.0 by addition of 5 M NaOH. The culture was stirred constantly at 250 rpm using two rushton type propellers. Anaerobic conditions were maintained by flushing the headspace of the reactor with CO2. After 8 h in batch mode the culture was run in continuous mode at a dilution rate of 0.1 h-1. Fresh medium was added using a peristaltic pump (Alitea, Bioengineering AG, Wald, Switzerland), and fermented broth harvested with a second peristaltic pump (Alitea, Bioengineering AG, Wald, Switzerland) set at a slightly higher flow rate. A stabilization period of 90 h (corresponding to nine reactor volume changes) was operated prior culture monitoring (t=0). Aliquots of 2 ml taken at t=31, 134 and 211 h were centrifuged (4,000 g, 1 min, room temperature) for transcriptomic analysis. Supernatants were discarded and cell pellets snap frozen in liquid nitrogen and stored at -80ºC until RNA-extraction. Keywords: Time course of Bifidobacterium longum in continuous culture
Project description:A continuous culture of Bifidobacterium longum NCC2705 was carried out in a 2.5-l reactor (Bioengineering AG, Wald, Switzerland), equipped with a Biospectra control system (Biospectra AG, Schlieren, Switzerland) and containing 2 l of MRS, added of 0.05% cysteine, inoculated with 2 % (v/v) preculture. The temperature was maintained at 37°C and the pH at 6.0 by addition of 5 M NaOH. The culture was stirred constantly at 250 rpm using two rushton type propellers. Anaerobic conditions were maintained by flushing the headspace of the reactor with CO2. After 8 h in batch mode the culture was run in continuous mode at a dilution rate of 0.1 h-1. Fresh medium was added using a peristaltic pump (Alitea, Bioengineering AG, Wald, Switzerland), and fermented broth harvested with a second peristaltic pump (Alitea, Bioengineering AG, Wald, Switzerland) set at a slightly higher flow rate. A stabilization period of 90 h (corresponding to nine reactor volume changes) was operated prior culture monitoring (t=0). Aliquots of 2 ml taken at t=31, 134 and 211 h were centrifuged (4,000 g, 1 min, room temperature) for transcriptomic analysis. Supernatants were discarded and cell pellets snap frozen in liquid nitrogen and stored at -80ºC until RNA-extraction. Keywords: Time course of Bifidobacterium longum in continuous culture Bifidobacterium longum NCC2705 at time 31 versus time 134 h and versus time 211 h in continuous culture. Two technical replicares with dyes swaps
Project description:Wastewater treatment plants use a variety of bioreactor types and configurations to remove organic matter and nutrients. Little is known regarding the effects of different configurations and within-plant immigration on microbial community dynamics. Previously, we found that the structure of ammonia-oxidizing bacterial (AOB) communities in a full-scale dispersed growth activated sludge bioreactor correlated strongly with levels of NO2- entering the reactor from an upstream trickling filter (Wells et al 2009). Here, to further examine this puzzling association, we profile within-plant microbial biogeography (spatial variation) and test the hypothesis that substantial microbial immigration occurs along a transect (raw influent, trickling filter biofilm, trickling filter effluent, and activated sludge) at the same full-scale wastewater treatment plant. AOB amoA gene abundance increased >30-fold between influent and trickling filter effluent concomitant with NO2- production, indicating unexpected growth and activity of AOB within the trickling filter. Nitrosomonas europaea was the dominant AOB phylotype in trickling filter biofilm and effluent, while a distinct ‘Nitrosomonas-like’ lineage dominated in activated sludge. Prior time series indicated that this ‘Nitrosomonas-like’ lineage was dominant when NO2- levels in the trickling filter effluent (i.e., activated sludge influent) were low, while N. europaea became dominant in the activated sludge when NO2- levels were high. This is consistent with the hypothesis that NO2- production may co-occur with biofilm sloughing, releasing N. europaea from the trickling filter into the activated sludge bioreactor. Phylogenetic microarray (PhyloChip) analyses revealed significant spatial variation in taxonomic diversity, including a large excess of methanogens in the trickling filter relative to activated sludge and attenuation of Enterobacteriaceae across the transect, and demonstrated transport of a highly diverse microbial community via the trickling filter effluent to the activated sludge bioreactor. Our results provide compelling evidence that substantial immigration between coupled process units occurs and may exert significant influence over microbial community dynamics within staged bioreactors.
2015-11-03 | GSE52079 | GEO
Project description:Biodegradation of real industrial wastewater containing ethylene glycol by using aerobic granular sludge in a continuous-flow reactor