Authors: Kevin Feris, Joni
Barnes, Cathy Rae, Patrick Sorenson, and Araya Kiepert
Affiliation:
Title: Novel Photoheterotrophs and Biological H2 Production from Potato Wastewater
Abstract: As a result of world oil
shortages and environmental concerns, there is a compelling need for new sources
of clean, inexpensive, and renewable energy.
Although hydrogen (H2) energy is a promising alternative to petroleum, to
achieve a sustainable hydrogen based economy, novel methods of H2 production
from renewable sources are needed.
Microbial degradation of biomass is one potential mechanism to satisfy this
need. Light-dependent
photoheterotrophic metabolism by nitrogen-fixing purple non-sulfur bacteria
(PNSB) can generate significant quantities of H2 from organic substrates.
If driven by essentially free biomass feedstocks, such as agricultural
wastewaters, these organisms may provide a method to efficiently generate
low-cost, carbon neutral H2. Work
by our group has demonstrated the ability of two PNSB, Rhodopseudomonas
capsulata and Rhodobacter sphaeroides, to produce H2 using potato processing
wastewater as their sole carbon and nitrogen source.
However, these organisms are not tolerant of low pH levels typical of
potato wastewater streams. To
eliminate the need for pH adjustment, we conducted enrichment studies to isolate
and cultivate novel acidophilic and acid tolerant strains of environmental PNSB.
As a result, a suite of 70 nitrogen-fixing photoheterotrophic
microorganisms were isolated from acidic peat bogs (pH 5-6) in