Jeong So-Yeon, Cho Kyung-Suk, Kim Tae Gwan
Global Top 5 Program, Department of Environmental Science and Engineering, Ewha Womans University, 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750, Republic of Korea.
Department of Ecosystem Function, Bureau of Basic Ecological Research, National Institute of Ecology, 1210, Geumgang-ro, Maseo-myeon, Seocheon-gun, Chungcheongnam-do 325-813, Republic of Korea.
Biotechnol Rep (Amst). 2014 Sep 26;4:128-133. doi: 10.1016/j.btre.2014.09.007. eCollection 2014 Dec.
Methanotrophs are a biological resource as they degrade the greenhouse gas methane and various organic contaminants. Several non-methanotrophic bacteria have shown potential to stimulate growth of methanotrophs when co-cultured, and however, the ecology is largely unknown. Effects of sp. NM1 on methanotrophic activity and growth of sp. M6 were investigated in this study. M6 and NM1 were mixed at mixing ratios of 9:1, 1:1, and 1:9 (v/v), using cell suspensions of 7.5 × 10 cells L. Methane oxidation of M6 was monitored, and M6 population was estimated using fluorescence hybridization (FISH). Real-time PCR was applied to quantify rRNA and expression of transcripts for three enzymes involved in the methane oxidation pathway. NM1 had a positive effect on M6 growth at a 1:9 ratio ( < 0.05), while no significant effects were observed at 9:1 and 1:1 ratios. NM1 enhanced the methane oxidation 1.34-fold at the 1:9 ratio. NM1 increased the population density and relative rRNA level of M6 by 2.4-fold and 5.4-fold at the 1:9 ratio, indicating that NM1 stimulated the population growth of M6. NM1 increased the relative transcriptional expression of all mRNA targets only at the 1:9 ratio. These results demonstrated that NM1 enhanced the methanotrophic activity and growth of M6, which was dependent on the proportion of NM1 present in the culture. This stimulation can be used as management and enhancement strategies for methanotrophic biotechnological processes.
甲烷氧化菌是一种生物资源，因为它们能够降解温室气体甲烷和各种有机污染物。几种非甲烷氧化菌在共培养时已显示出刺激甲烷氧化菌生长的潜力，然而，其生态学在很大程度上尚不清楚。本研究调查了NM1菌株对M6菌株甲烷氧化活性和生长的影响。将M6和NM1以9:1、1:1和1:9（v/v）的混合比例混合，使用7.5×10个细胞/升的细胞悬液。监测M6的甲烷氧化情况，并使用荧光原位杂交（FISH）估计M6的菌群数量。应用实时定量PCR来量化参与甲烷氧化途径的三种酶的rRNA和转录本表达。NM1在1:9的比例下对M6的生长有积极影响（P<0.05），而在9:1和1:1的比例下未观察到显著影响。在1:9的比例下，NM1使甲烷氧化增强了1.34倍。在1:9的比例下，NM1使M6的菌群密度和相对rRNA水平分别增加了2.4倍和5.4倍，表明NM1刺激了M6的菌群生长。仅在1:9的比例下，NM1增加了所有mRNA靶标的相对转录表达。这些结果表明，NM1增强了M6的甲烷氧化活性和生长，这取决于培养物中NM1的比例。这种刺激可作为甲烷氧化生物技术过程的管理和增强策略。
