亚硝氮对海洋着色菌亚硝氮和氨氮去除以及光合色素合成的影响

Effects of nitrite on ammonia-nitrogen removal and nitrite-nitrogen as well as photopigment biosynthesis of Marichromatium gracile YL28

摘要:

【目的】在以亚硝氮为唯一氮源和亚硝氮-氨氮共存体系中，考察和分析海洋着色菌(Marichromatium gracile) YL28菌株对水体亚硝氮的环境适应能力。【方法】采用分光光度法分析亚硝氮、氨氮去除效率以及亚硝氮对菌体生物量和色素含量的影响，采用薄层层析法分析亚硝氮对菌体光合色素组成的影响。【结果】YL28菌株能以亚硝氮为唯一氮源生长，主要积累2种细菌叶绿素(BChl)组分(BChl aTHGG和BChl ap)、1种细菌脱镁叶绿素(Bphe)和玫红品(Rhodopin)、螺菌黄质(Spirilloxanthin)、脱水紫菌红醇(Anhydro rhodovibrin)、番茄红素(Lycopene) 4种类胡萝卜素(Car)；YL28生物量和对亚硝氮的去除效率随亚硝氮浓度升高而降低，完全去除亚硝氮的浓度可达200 mg/L以上；当亚硝氮浓度高于25 mg/L，单位质量菌体BChl a和Car总量降低，BChl a和Car合成的末端产物(BChl ap和Spirilloxanthin)以及Bphe相对含量升高，其它4种色素组分相对含量则降低，但Car与BChl a相对含量的比值未见明显变化。当亚硝氮-氨氮共存时，YL28菌株对亚硝氮的耐受能力和去除能力明显提高，完全去除亚硝氮的浓度可达300 mg/L以上；氨氮减缓了亚硝氮对光合色素合成的抑制作用，提高了菌体色素合成总量，各色素组分相对含量的变化与亚硝氮为唯一氮源时的变化规律一致。【结论】YL28菌株能高效去除亚硝氮，亚硝氮对菌株生长和光合色素的合成有抑制作用，但氨氮能明显提高YL28菌株对亚硝氮的适应能力。这为进一步开发高效脱除亚硝氮的APB水质调节剂奠定了基础。

Abstract:

[Objective] To understand the adaptability of Marichromatium gracile YL28 to nitrite environment. [Methods] When YL28 was grown with nitrite as the sole nitrogen source or with nitrite-ammonium as coexisting nitrogen sources, the removal efficiency of ammonium-nitrogen and nitrite-nitrogen, the effect of nitrite on bacterial growth and total amounts of photopigments including carotenoids and bacterio chlorophylls were studied by spectrophotometry. The effect of nitrite on compositions of carotenoid and bacteriochlorophyll was investigated by thin layer chromatography. [Results] Strain YL28 was capable of growing with nitrite as the sole nitrogen sources; mainly accumulated two BChl a intermediates (BChl aTHGG and BChl ap), bacterio pheophytin (BPhe) and four carotenoids (rhodopin, spirilloxanthin, anhydro rhodovibrin and lycopene). Bacterial growth and nitrite removal efficiency were decreased with increasing nitrite concentration, more than 200 mg/L of nitrite could be completely removed by strain YL28. When nitrite concentration reached to 25 mg/L, the total amounts of carotenoid and bacteriochlorophyll were decreased dramatically, whereas the relative contents of BChl ap (end product of BChl a biosynthesis), spirilloxanthin (end product of carotenoids biosynthesis) and Bphe increased. When YL28 was grown with nitrite-ammonium as coexisting nitrogen source, the tolerance of YL28 to nitrite and removal efficiency of nitrite by YL28 were significantly enhanced compared with nitrite as the sole nitrogen source, more than 300 mg/L of nitrite was completely eliminated by strain YL28. The inhibitory of nitrite on photopigment biosynthesis was alleviated, the total amounts of carotenoid and bacteriochlorophyll were enhanced, the changes in photopigment compositions were similar to those with nitrate as the sole nitrogen sources. [Conclusion] YL28 could remove nitrite. High concentration nitrite inhibited bacterial growth and photopigment biosynthesis, but the presence of ammonium together with nitrite could promote the tolerance of strain YL28 to nitrite. This work should be helpful to develop novel marine water cleaner for high efficient removal of nitrite.