Supporting information Membrane bioreactors fed with different COD/N ratio wastewater: impacts on microbial community and microbial products Xiaomeng Han1, Zhiwei Wang1,*, Jinxing Ma1, Chaowei Zhu2, Yaxin Li1, Zhichao Wu1 1 State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, P.R. China 2 Chinese Research Academy of Environmental Sciences, Beijing 100012, P.R. China * Corresponding author. Tel./fax: +86-21-65980400. E-mail address: zwwang@tongji.edu.cn S1 Contents Microbial diversity analysis procedure Fig. S1 Schematic diagram of M1 and M2 Fig. S2 Venn diagram of the bacterial communities of M1 and M2 based on OTU (3% distance), and the taxonomic identities at the phylum level. M1-U and M2-U represent the unique M1 and M2 communities, and M1-M2 refers to shared communities Fig. S3 Variations of relative abundances of the predominant phylogenetic group at the phylum level in MBRs; (a) the relative abundance, (b) statistical analysis of the difference; relative abundance is defined as the number of sequences affiliated with that taxon divided by the total number of sequences per sample; “No_Rank” are defined as the sequences that are embodied in the database but without taxonomic classification; phyla making up less than 0.5 % are defined as “others” Fig. S4 EEM fluorescence spectra of (a) SMP of M1, (b) SMP of M2, (c) LB-EPS of M1, (d) LB-EPS of M2, (e) TB-EPS of M1, (f) TB-EPS of M2; Peak A indicates aromatic protein-like substances, Peak B indicates tryptophan protein-like substances and Peak C indicates visible humic acid-like substances Fig. S5 Comparison of the fluidity of SMP and bound EPS extracted from M1 and M2: Dissipation shift (△D) versus frequency shift (△f) during adsorption stage Fig. S6 Component percentage changing of SMP and bound EPS excreted in the batch tests; (a) SMP in M1 sludge, (b) SMP in M2 sludge, (c) LB-EPS in M1 sludge, (d) LB-EPS in M2 sludge, (e) TB-EPS in M1 sludge, (f) TB-EPS in M2 sludge Table S1 Richness and diversity estimators of the bacteria phylotypes in MBRs S2 Microbial diversity analysis procedure Based on the manufacturer’s protocols, DNA extraction was conducted by FastDNA®SPIN Kit for Soil (MP Biomedicals, Solon, OH, USA). Afterwards, the quality of the DNA fragments was measured via a Nano-drop® ND-1000 spectrophotometer (Labtech International, UK). DNA were amplified by PCR with thermocycling steps using primer set 27F (5’-AGAGTTTGATCCTGGCTCAG-3’) and 533R (5’-TTACCGCGGCTGCTGGCAC-3’) with the aim of the V1-V3 region of the 16S rRNA gene. 0.4 μL of FastPfu Polymerase, 4 μL of 5×FastPfu Buffer, 0.4 μL of each primer (5 μM), 2 μL of 2.5 mM dNTPs and 0.5 μL of DNA were included in the PCR mixture of 20 μL. During the thermocycling steps, denaturation at 95°C for 2 min was first employed. Then 25 cycles of 95°C for 30 sec, 55°C for 30 sec, 72°C for 30 sec were applied, followed by a final extension step at 72°C for 5 min. A 10-nucleotide barcode, which was inserted between the Life Science primer A and the 27F primer, was incorporated in the fused forward primer. During pyrosequencing in a single 454 GS-FLX run, these barcodes enabled samples to multiplex. The mixture of amplicons was purified with the UNIQ-10 PCR Purification Kit (Sangon, Shanghai, China) and quantified with a TBS-380 (Turner BioSystems, Inc., USA). Then the amplicons were used for pyrosequencing on a Roche 454 GS-FLX Titanium platform (Roche 454 Life Sciences, Branford, CT, USA) according to the method reported by Margulies et al. (2005). In order to improve the veracity of data, the low-quality sequences shorter than 200 bp which could not match the forward primer or possessed an unrecognizable reverse primer or contained any ambiguous base calls, were removed (Lu et al. 2012). After eliminating the low-quality sequences and stripping barcodes and primers, 6940 (R1) and 6867 (R2) high-quality V1-V3 tags of the 16S rRNA-gene were produced with an average length was 473 bp. S3 Finally, a kmer searching (http://www.mothur.org/wiki/Align.seqs) was performed to analyze the resulting sequences based on the silva database ( http://www.arb-silva.de ). The uniform length was 200 bp. According to the furthest neighbor method in MOTHUR program (http://www.mothur.org/wiki/Cluster), the high-quality reads were clustered into operational taxonomic units (OTUs) with a 0.03 or 0.05 distance limit (corresponding to 97% or 95% similarity). Taxonomic classification was assigned down to the phylum and genus level using Naïve Bayesian Classifier method (http://www.mothur.org/wiki/Classify.seqs ) with a set confidence threshold of 80%. Effluent Carbon source added Influent coming from a dynamic membrane separation reactor with carbon source added A/O MBR, M1 Effluent Influent coming from a dynamic membrane separation reactor A/O MBR, M2 Fig. S1 Schematic diagram of M1 and M2 S4 2500 No_Rank Acidobacteria Actinobacteria Bacteroidetes 2000 Chlorobi Chloroflexi Cyanobacteria 1500 OTUs Elusimicrobia Firmicutes Fusobacteria Gemmatimonadetes 1000 Lentisphaerae Nitrospirae Planctomycetes 500 Proteobacteria Spirochaetes Tenericutes Verrucomicrobia 0 M₁-U M₁-M₂ M₂-U M1-U 1581 OTUs M2-U M1-M2 526 OTUs 2246 OTUs Fig. S2 Venn diagram of the bacterial communities of M1 and M2 based on OTU (3% distance), and the taxonomic identities at the phylum level. M1-U and M2-U represent the unique M1 and M2 communities, and M1-M2 refers to shared communities S5 M1 M2 Bacteroidetes Proteobacteria Nitrospirae No_Rank Chloroflexi others Planctomycetes Acidobacteria Gemmatimonadetes Chlorobi Candidate_division_TM7 Verrucomicrobia Lentisphaerae (a) (b) Fig. S3 Variations of relative abundances of the predominant phylogenetic group at the phylum level in MBRs; (a) the relative abundance, (b) statistical analysis of the difference; relative abundance is defined as the number of sequences affiliated with that taxon divided by the total number of sequences per sample; “No_Rank” are defined as the sequences that are embodied in the database but without taxonomic classification; phyla making up less than 0.5 % are defined as “others” S6 0 550 (a) 3.467E4 (b) 3.467E4 1.040E5 6.933E4 500 1.387E5 450 1.040E5 1.733E5 1.387E5 450 2.080E5 400 1.733E5 2.427E5 2.600E5 2.080E5 Ex (nm) Ex (nm) 0 550 6.933E4 500 350 400 2.427E5 2.600E5 350 300 300 250 250 300 350 400 450 500 250 550 Em (nm) 250 300 350 400 450 500 550 Em (nm) -6.000E4 550 (c) 5.467E4 (d) Peak C 2.840E5 5.133E5 3.987E5 450 6.280E5 Peak B 400 1.693E5 500 3.987E5 5.133E5 7.427E5 8.000E5 6.280E5 Ex (nm) Ex (nm) 5.467E4 2.840E5 450 350 300 -6.000E4 550 1.693E5 500 Peak A 400 7.427E5 8.000E5 350 300 250 250 300 350 400 450 500 250 550 Em (nm) 250 300 350 400 450 500 550 Em (nm) -2.000E5 550 (e) 1.200E5 (f) 1.200E5 7.600E5 4.400E5 500 1.080E6 450 7.600E5 1.400E6 1.080E6 450 1.720E6 400 1.400E6 2.040E6 2.200E6 1.720E6 Ex (nm) Ex (nm) -2.000E5 550 4.400E5 500 350 400 2.040E6 2.200E6 350 300 300 250 250 300 350 400 450 500 250 550 Em (nm) 250 300 350 400 450 500 550 Em (nm) Fig. S4 EEM fluorescence spectra of (a) SMP of M1, (b) SMP of M2, (c) LB-EPS of M1, (d) LB-EPS of M2, (e) TB-EPS of M1, (f) TB-EPS of M2; Peak A indicates aromatic protein-like substances, Peak B indicates tryptophan protein-like substances and Peak C indicates visible humic acid-like substances S7 15 M₁:SMP Dissipation shift, △D (10 -6 ) 12 9 y = -0.4028x - 0.0148 R² = 0.9888 M₂:SMP y = -0.2228x + 0.0079 R² = 0.9472 M₁:LB-EPS y = -0.3590x - 1.2737 R² = 0.9977 M₂:LB-EPS y = -0.3369x - 0.7880 R² = 0.9973 M₁:TB-EPS y = -0.3114x + 0.8377 R² = 0.9986 M₂:TB-EPS y = -0.2882x + 1.0710 R² = 0.998 6 3 0 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 Frequency shift, △f (Hz) Fig. S5 Comparison of the fluidity of SMP and bound EPS extracted from M1 and M2: Dissipation shift (△D) versus frequency shift (△f) during adsorption stage S8 Humic acids Carbohydrates Proteins 100% 80% 80% Percentage Percentage Proteins 100% 60% 40% Humic acids 60% 40% 20% 20% 0% 0% 0 1 2 3 4 5 0 6 1 2 (a) 4 5 6 (b) Humic acids Carbohydrates Proteins 100% 100% 80% 80% Percentage Percentage Proteins 3 Time (h) Time (h) 60% 40% 20% Humic acids Carbohydrates 60% 40% 20% 0% 0% 0 1 2 3 4 5 6 0 1 2 Time (h) Proteins 3 4 5 6 Time (h) (c) (d) Humic acids Carbohydrates Proteins 100% 100% 80% 80% Percentage Percentage Carbohydrates 60% 40% 20% Humic acids Carbohydrates 60% 40% 20% 0% 0% 0 1 2 3 4 5 6 0 1 2 Time (h) 3 4 5 6 Time (h) (e) (f) Fig. S6 Component percentage changing of SMP and bound EPS excreted in the batch tests; (a) SMP in M1 sludge, (b) SMP in M2 sludge, (c) LB-EPS in M1 sludge, (d) LB-EPS in M2 sludge, (e) TB-EPS in M1 sludge, (f) TB-EPS in M2 sludge S9 Table S1 Richness and diversity estimators of the bacteria phylotypes in MBRs α=0.03 Sample OTU Chao1a M1 2107 6460 5.45 M2 2772 8908 6.82 α=0.05 Shannon b Coverage c OTU Chao1a Shannon b Coverage c 0.78 1796 4891 5.19 0.82 0.70 2371 6594 6.56 0.76 References: Lu L, Xing D, Ren N (2012) Pyrosequencing reveals highly diverse microbial communities in microbial electrolysis cells involved in enhanced H2 production from waste activated sludge. Water Res 46: 2425-2434 Margulies M, Egholm M, Altman WE, Attiya S, Bader JS, Bemben LA, Berka J, Braverman MS, Chen YJ, Chen ZT (2005) Genome sequencing in microfabricated high-density picolitre reactors. Nature 437: 376-380 S10