Study of methanol-induced phenotypic changes in a novel strain of Acinetobacter lwoffii

Abstract

A Gram-negative bacterial strain designated LS2 isolated from Lahaul-Spiti valley of North India was shown to produce pink pigment while utilizing methanol as sole source of carbon and energy. Interestingly, pigment production was inducible in nature since the organism did not produce any pigment when grown on other carbon sources. Based on phenotypic and phylogenetic characterization the non-pigmented methylotroph was identified as a novel strain of Acinetobacter lwoffii MTCC 8288 (DQ144736). By means of spectral and mass analyses the pigment was characterized as bacterioruberin-like carotenoid molecule. Here, the carotenoid pigment may form an important part of the antioxidant defense mechanism against oxidative stress imparted by methanol. The methanol utilization pathway in strain LS2 was deciphered by showing the presence of functional methanol dehydrogenase and formaldehyde dehydrogenase genes. In addition, to investigate methanol induced physiological changes, comparative fatty acid profile was analysed and distinctive qualitative as well as quantitative differences in fatty acid content were observed. Therefore, we suggest that strain LS2 exhibiting such unique phenotypic property should be assigned a taxonomic position other than the pigmented and non-pigmented methylotrophs.

Culturable Facultative Methylotrophic Bacteria from the Cactus <i>Neobuxbaumia macrocephala</i> Possess the Locus <i>xoxF</i> and Consume Methanol in the Presence of Ce³⁺ and Ca²⁺

“…( Gammaproteobacteria ) were the most frequently isolated organisms. It has been reported that Acinetobacter uses methanol as a carbon source ( 20 , 61 ) and a methanol dehydrogenase sequence coding Asp 301 has previously been detected in this genus ( 20 ). Similar to these findings, other studies identified Proteobacteria and Actinobacteria as some of the most common taxa in the rhizosphere and soil from cacti and other plants from arid lands ( 2 , 11 , 13 , 26 ).…”

Acidochromogenicity is a common characteristic in nontuberculous mycobacteria

“…These stresses include hyper osmolarity, UV light exposure, methanol exposure, elevated temperature, and low iron [8-10]. Many of these stresses result in increased oxidative damage within the microbial cell and pigments have been shown to decrease the overall level of reactive oxygen intermediates [11,12].…”

Novel methylotrophic bacteria isolated from the River Thames (London, UK)

“…Methylobacterium , Methylomonas , Methylosinus , Methyloversatilis , Bacillus methanolicus ; Whittenbury et al ., 1970; Arfman et al ., 1992; Kalyuzhnaya et al ., 2006; Lidstrom, 2006). The occurrence of methylotrophy in prokaryotes was subsequently realized not to correlate with traditional bacterial classification (Brautaset et al ., 2004), as facultative methylotrophy was progressively shown to be a property of diverse typically heterotrophic genera including Paracoccus , Hyphomicrobium , Micrococcus , Arthrobacter , Brevibacterium , Beijerinckia , Bacillus , Klebsiella , Afipia , Variovorax , Amycolatopsis , Mycobacterium and Acinetobacter (Nishio et al ., 1975; Bamforth and Quayle, 1978; Duménil et al ., 1979; Levering et al ., 1981; Nazina, 1981; Dijkhuizen et al ., 1988; Kato et al ., 1988; Nesvera et al ., 1991; Cercel, 1999; Mitsui et al ., 2000; Alves et al ., 2001; Borodina et al ., 2002; Anesti et al ., 2005; Dedysh et al ., 2005b; Moosvi et al ., 2005a,b; Kelly et al ., 2006; Lidstrom, 2006; Ghosh et al ., 2007). The ribulose monophosphate (RuMP) cycle and its key enzymes (3‐hexulose‐6‐phosphate synthase and 6‐phospho‐3‐hexulose isomerase) were once regarded as diagnostic characters of some methylotrophs (Dijkhuizen et al ., 1992), but are now known to be widespread among bacteria and Archaea , for formaldehyde fixation and detoxification, and ribulose 5‐phosphate biosynthesis in Archaea (Reizer et al ., 1997; Yasueda et al ., 1999; Kato et al ., 2006; Orita et al ., 2006).…”