Arsenic tolerance of cyanobacterial strains with potential use in biotechnology

Abstract

The arsenic content of various water bodies in Argentina is higher than the acceptable levels for human and animal uses. Cyanobacteria are widely distributed in aquatic environments and can bioaccumulate arsenic (As). This study presents the response of indigenous cyanobacteria to As(III) and As(V), including the species Tolypothrix tenuis, Nostoc muscorum and Nostoc minutum, previously used with biotechnological purposes. As(III) resulted more toxic than As(V) in all cases, causing cell death in the range of 5-20 mg/l. T. tenuis growth was sensitive to As(V) with lethal inhibition at 625 mg/l, whereas the Noctoc species were stimulated. EC50 values found were 73.34 mg/l for N. muscorum and 989.3 mg/l for N. minutum. Batch cultures of N. minutum showed improvements in both growth parameters and photosynthetic pigment content in the presence of 1,000 mg/l As(V). Increases of 66.7%, 75.5%, 40% and 20.7% in cell productivity, chlorophyll a, total carotenoids and C-phycocyanin respectively were observed, reaching a bioaccumulated arsenic value of 37.4 ¼g/g at the stationary growth phase.

Probing Synechocystis-Arsenic Interactions through Extracellular Nanowires

“…As (III) showed more toxicity (~100 times) to Synechocystis cells than As (V) ( Figure 1 , Supplementary Figure S1 ). Similar results have been observed in other cyanobacteria like Microcystis aeruginosa , Nostoc muscorum, N. minutum , and Tolypothrix tenuis ( Ferrari et al, 2013 ; Wang et al, 2013 ).…”

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review

“…Carotenoids–accessory photosynthetic pigments, are fat-soluble tetraterpenoid molecules that are divided into no oxygen-containing carotenes (β-carotene) and oxygen-containing xanthophylls (lutein, astaxanthin, zeaxanthin) [ 91 ]. Phycobiliproteins are water-soluble proteins that serve as accessory pigments in blue-green or red microalgae, giving a blue (c-phycocyanin, allophycocyanin) [ 34 , 92 ] or pink, red (b-phycoerythrin, c-phycoerythrin) [ 93 , 94 ] colour. Chlorophylls, carotenoids and Phycobiliproteins can find applications in food, cosmetic and pharmaceutical products as coloring, antioxidant, food additive or therapeutic agents [ 95 , 96 , 97 ].…”

“…Also, β-carotene content in Dunaliella salina cells was increased seven times in the presence of 450 µM Fe 2+ and 67.5 mM acetate, however at the expense of four-fold reduction in Dunaliella cell number [ 105 ]. Cyanobacterium Nostoc minutum cultivated photoautotrophically in medium containg 1 g/L arsenic(V) was reported to posses chlorophyll, carotenoid and allophycocyanin content higher by 75%, 40% and 25%, respectively, when compared to control culture [ 34 ]. Similarly, small concentrations of Ni (0.1–10 µM) increased chlorophyll content and c-phycocyanin production even by 47% and up to 4.35 times, respectively, in Anabaena doliolum culture [ 92 ].…”

“…Lead, aluminum [ 26 ] and cobalt [ 33 ] at low concentrations had stimulatory effect on growth of Dunaliella tertiolecta [ 26 ] and Monoraphidium minutum [ 33 ]. Arsenic (As(V)) was reported to improve the growth of cyanobacterium Nostoc minutum [ 34 ] and microalgae Chlorella salina [ 35 ] and Chlorella sp. [ 36 ].…”

Assessment of the effects of As(III) treatment on cyanobacteria lipidomic profiles by LC-MS and MCR-ALS

“…Arsenic (As) is a well-known toxic element naturally present in the Earth's crust [1]. Several studies have shown the different responses of microorganisms exposed to this metal, such as the demethylation process in fungi [2], contamination in food [3], and bioaccumulation, transformation, and release in Microcystis [4].…”