Chitinolytic bacteria from alkaline hypersaline Mono Lake, California, USA

Abstract

Chitinolytic activity was detected in sediment and water-column samples from Mono Lake, California, USA, using fluorogenic analogues. In order to learn more about chitin degradation in Mono Lake, we analyzed the phylogenetic composition of bacterial assemblages in chitin-enrichment cultures and associated with Artemia monica exuvia. We also isolated chitinolytic bacteria from aerobic and anaerobic water and sediment samples. We screened these isolates for their ability to hydrolyze chitin analogs, for the formation of clearing zones on chitin plates, and for growth with chitin as the sole carbon and energy source. We characterized the isolates phylogenetically by determining partial sequences of their 16S rRNA genes. Three ribotypes, most closely related to Paracoccus sp. MBIC4036 (AB025192), Arhodomonas sp. EL-201 (AJ315984), and Psychroflexus tropicus (AF513434), were only found in Mono Lake exuvium and chitin-enrichment clone libraries. Four ribotypes, retrieved solely from chitin enrichments, were closely related to Proteobacteria. The majority (73%) of the isolates we obtained were Gram-positive bacteria, and 70% of the Gram-positive isolates were capable of hydrolyzing at least 1 model substrate. © Inter-Research 2006.