1. Target Enzyme or Product
Bioprospecting for Glycohydrolase- and 1,2-Propanediol-producing Microorganisms from Geothermal Intertidal Pools in Northern Iceland
Pia Maria Iloranta, Jón Pétur Jóelsson, Sean Michael Scully, Jóhann Örlygsson*
*Corresponding author
University of Akureyri Borgir v/v Norðurslóð 600 Akureyri, Iceland
Abstract
Macro algae species are promising feedstocks for biotechnological applications. Unlike terrestrial lignocellulosic biomass, macro algae lack lignin but contain a much broader range of polysaccharides. Enzymes for the degradation of polysaccharides found in macro algae such as agar, alginate, fucoidan, laminarin, and ulvan are not available. Solutions for the degradation of xylan and cellulose, however, are commercially available. The aim of the work has been to bioprospect geothermally-heated intertidal pools north of Húsavík for microbes producing 1,2-propanediol and/or glycohydrolases capable of degrading the polysaccharides found in macro algae. The temperature in the sampled geothermal pools ranged from 22 to 67°C. Samples were collected and enriched on various polysaccharides (laminarin, ulvan, fucoidan, agar, alginate, cellulose) as well as single carbohydrates (glucose, L-rhamnose, and L-fucose). A total of 195 isolates were obtained and characterized using standard phenotypic methods including API 20E, API ZYM panels and 16S rRNA. 1,2-PD was produced by 68 of the isolates from either glucose, rhamnose, or fucose. Enzymatic activities of the isolates are yet to be confirmed.
1 Introduction
3 Results and Discussion
3.1 Isolation and Characterization
Macro algae species are potential feed-stocks for biofuel and fine chemical production
Contain diverse polysaccharides
Lack of commercially available enzymes for degradation is a major barrier
Aim of this work is to
Isolate glycohydrolases for macro algae processing
Produce 1,2-propanediol with bacteria
195 isolates
Majority of 1,2-PD producing isolates were enteric pathogens
1 isolate from 65° (B. licheniformis)
68 1,2-PD producers
117 VP positive strains
Isolated strains were characterized by sequencing of the 16S rDNA gene. Only 1,2-PD producers were sequenced
2 Materials and Methods
Samples were collected from six geothermal intertidal pools
3.2 Glycohydrolases and Other Enzymes
46+ strains degrade starch
26+ strains degrade β-glucan
51+ strains mobilize inorganic phosphate
Work on algal polysaccharide degradation is ongoing (agar, alginate, fucoidan, ulvan, laminarin, etc)
The pools north of Húsavík ranged in temperature from 23 to 65°C. Macro algae debris that has washed into the pool is visible
3.3 Evaluation of 1,2-Propanediol Production
20 of the 1,2-PD positive strains were screened at various concentrations of glucose & rhamnose (10 to 60 mM)
Selected strains were grown on glu, rha, glu+rha, and 1,2-PD kinetically
Palmaria palmata – a source of alginate and agar
Ulva intestinalis – a source of ulvan
Enrichment Medium
Target Enzyme or Product
Cellulose
Cellulase
Fucoidan
Fucosidase
Ulvan
Ulvanase
Laminarin
Laminarase
Alginate
Alginate lyase
Agar
Agarase
Tryptone
Proteases
Chitin
Chitinases
L-Fucose
1,2-Propanediol
L-Rhamnose
D-Glucose
Non-specific
Samples enriched 3x
Time (h)
Time (h)
Shigella sonnei strain D1A grown on L-rhamnose (20 mM, left) and glu+rha (20 mM each, right)
3.4 Future Directions
Isolates characterized by 16S rDNA and screened for 1,2-PD production and glycohydrolase production
Further characterization by API 20E, API ZYM, and API 50CH
Bioprocessing of macro algae
Fermentation of macro algae hydrolysates for the production of high-value products