TY - JOUR
T1 - Effects of phosphate limitation on soluble microbial products and microbial community structure in semi-continuous Synechocystis-based photobioreactors
AU - Zevin, Alexander S.
AU - Nam, Taekgul
AU - Rittmann, Bruce
AU - Krajmalnik-Brown, Rosa
PY - 2015/9/1
Y1 - 2015/9/1
N2 - All bacteria release organic compounds called soluble microbial products (SMP) as a part of their normal metabolism. In photobioreactor (PBR) settings, SMP produced by cyanobacteria represent a major pool of carbon and electrons available to heterotrophic bacteria. Thus, SMP in PBRs are a major driver for the growth of heterotrophic bacteria, and understanding the distribution of SMP in PBRs is an important step toward proper management of PBR microbial communities. Here, we analyzed the SMP and microbial communities in two Synechocystis sp. PCC6803-based PBRs. The first PBR (PBRP0) became phosphate limited after several days of operation, while the second PBR (PBRP+) did not have phosphate limitation. Heterotrophic bacteria were detected in both PBRs, but PBRP0 had a much higher proportion of heterotrophic bacteria than PBRP+. Furthermore, PBRP+ had greater biomass production and lower SMP production per unit biomass than PBRP0. Carbohydrates that were most likely derived from hydrolysis of extracellular polymeric substances (EPS) dominated the SMP in PBRP0, while products resulting from cell lysis or decay dominated the SMP in PBRP+. Together, our data support that maintaining phosphate availability in Synechocystis-based PBRs is important for managing SMP and, thus, the heterotrophic community.
AB - All bacteria release organic compounds called soluble microbial products (SMP) as a part of their normal metabolism. In photobioreactor (PBR) settings, SMP produced by cyanobacteria represent a major pool of carbon and electrons available to heterotrophic bacteria. Thus, SMP in PBRs are a major driver for the growth of heterotrophic bacteria, and understanding the distribution of SMP in PBRs is an important step toward proper management of PBR microbial communities. Here, we analyzed the SMP and microbial communities in two Synechocystis sp. PCC6803-based PBRs. The first PBR (PBRP0) became phosphate limited after several days of operation, while the second PBR (PBRP+) did not have phosphate limitation. Heterotrophic bacteria were detected in both PBRs, but PBRP0 had a much higher proportion of heterotrophic bacteria than PBRP+. Furthermore, PBRP+ had greater biomass production and lower SMP production per unit biomass than PBRP0. Carbohydrates that were most likely derived from hydrolysis of extracellular polymeric substances (EPS) dominated the SMP in PBRP0, while products resulting from cell lysis or decay dominated the SMP in PBRP+. Together, our data support that maintaining phosphate availability in Synechocystis-based PBRs is important for managing SMP and, thus, the heterotrophic community.
KW - Bioenergy
KW - Biofuel
KW - Microbial ecology
KW - Photobioreactor
KW - Soluble microbial products
UR - http://www.scopus.com/inward/record.url?scp=84937735191&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84937735191&partnerID=8YFLogxK
U2 - 10.1002/bit.25602
DO - 10.1002/bit.25602
M3 - Article
C2 - 25851150
AN - SCOPUS:84937735191
VL - 112
SP - 1761
EP - 1769
JO - Biotechnology and Bioengineering
JF - Biotechnology and Bioengineering
SN - 0006-3592
IS - 9
ER -