ABSTRACT
Aims@#Pigments used as food additives for a long time and people prefer natural pigment than synthetic ones because of their safety. Microorganisms are interesting for pigment production and many of them have been used in food industry. Many research have been conducted to find out for natural pigment sources. The objective of this research was to investigate the characteristics of a red-pigmented bacteria isolated from Gedong Songo hot spring, Bandungan- Indonesia. @*Methodology and results@#Bacterial isolates were grown on Nutrient Agar for 24 h, and the morphology of the colonies and of the cells were identified. Biochemical tests included indole, methyl red, catalase, urease tests and carbohydrate fermentation. Molecular identification was based on 16S rRNA sequence. The isolate was a rod shape and Gram-negative. Biochemical tests showed that the isolate was indole negative, catalase positive, methyl red negative and urease negative. This isolate was glucose, maltose and sucrose positive and negative for lactose. 16S rRNA sequence was BLAST and it matched with Serratia marcescens strain S823. The red pigment antioxidant activity showed the highest DPPH radical scavenging of 49.11% obtained from 48 h of incubation. Functional group of S. marcescens pigment on Fourier Transform InfraRed Spectroscopy (FTIR) displayed specific peak at 1740 cm-1 represented of C═O (carbonyl) stretching group. @*Conclusion, significance and impact of study@#Based on morphological, biochemical and moleculer identifications, it showed that the bacteria isolated from Gedong Songo hot spring Bandungan-Indonesia had 94% homology with Serratia marcescens strain S823. Based on DPPH radical scavenging test, it demonstrated that S. marcescens had potency as an antioxidant.
ABSTRACT
This study presented an approach by combining the real-time reverse transcription polymerase chain reaction with the terminal restriction fragment length polymorphism (T-RFLP) to investigate transcriptional responses of ammonia-oxidizing bacteria (AOB) to dimethyl sulfide (DMS) inhibition. Batch experiments with added ammonium and DMS were conducted using three activated sludges and Nitrosomonas europaea, and the transcriptional responses of the amo subunit A (amoA) mRNA were evaluated. It was found that DMS inhibited ammonium oxidation and amoA mRNA expression in all batch experiments but the inhibition degree observed was different for different sludges examined. It is likely that the different inhibitory effects of DMS on ammonium oxidation and amoA mRNA expression stemmed from different dominant AOB populations in the sludges. The T-RFLP results for amoA mRNA suggested that inhibition of ammonium oxidation by DMS to Nm. europaea-like AOB with T-RF 219/270 is relatively minor compared to other AOB populations in the examined sludges, such as Nm. europaea-like AOB with T-RF 491/491.
Subject(s)
Bacteria/genetics , Genes, Bacterial , Microbiota/genetics , Sulfides/pharmacology , Transcription, Genetic/drug effects , Aerobiosis/drug effects , Anaerobiosis/drug effects , Bacteria/drug effects , Batch Cell Culture Techniques , Gene Expression Regulation, Bacterial/drug effects , Microbiota/drug effects , Molecular Sequence Data , Nitrogen/analysis , Polymorphism, Restriction Fragment Length , RNA, Messenger/genetics , RNA, Messenger/metabolism , Real-Time Polymerase Chain Reaction , Sewage/microbiology , Sulfur/analysisABSTRACT
This study investigated the linkage between performance of two full-scale membrane bioreactor (MBR) systems treating thin-film transistor liquid crystal display (TFT-LCD) wastewater and the population dynamics of dimethylsulfoxide (DMSO)/dimethylsulfide (DMS) degrading bacteria. High DMSO degradation efficiencies were achieved in both MBRs, while the levels of nitrification inhibition due to DMS production from DMSO degradation were different in the two MBRs. The results of real-time PCR targeting on DMSO/DMS degrading populations, including Hyphomicrobium and Thiobacillus spp., indicated that a higher DMSO oxidation efficiency occurred at a higher Hyphomicrobium spp. abundance in the systems, suggesting that Hyphomicrobium spp. may be more important for complete DMSO oxidation to sulfate compared with Thiobacillus spp. Furthermore, Thiobacillus spp. was more abundant during poor nitrification, while Hyphomicrobium spp. was more abundant during good nitrification. It is suggested that microbial population of DMSO/DMS degrading bacteria is closely linking to both DMSO/DMS degradation efficiency and nitrification performance.
