Nutrient-enhanced survival of and phenanthrene mineralization by alginate-encapsulated and free Pseudomonas sp. UG14Lr cells in creosote-contaminated soil slurries

Abstract

The effects of nutrient amendment and alginate encapsulation on survival of and phenanthrene mineralization by the bioluminescent Pseudomonas sp. UG14Lr in creosote-contaminated soil slurries were examined. UG14Lr was inoculated into creosote-contaminated soil slurries either as a free cell suspension or encapsulated in alginate beads prepared with montmorillonite clay and skim milk. Additional treatments were free-cell-inoculated slurries amended with sterile alginate beads, free-cell-inoculated and uninoculated slurries amended with skim milk only, and uninoculated, unamended slurries. Mineralization was determined by measuring 14CO2 released from radiolabelled phenanthrene. Survival was measured by selective plating and bioluminescence. Inclusion of skim milk was found to enhance both survival of and phenanthrene mineralization by free and encapsulated UG14Lr cells.

Federal Integrated Biotreatment Research Consortium (FIBRC): Flask to Field Initiative

“…The addition of biosurfactant stimulated indigenous bacteria to degrade hydrocarbons at higher rates than those achieved by nutrient addition alone (Atlas, 1993). Contradictory results are found in the literature concerning the effects of biosurfactants on PAH biodegradation Churchill et al, 1995;Deschenes et al, 1996;Finnerty, 1994;Miller, 1995;Providenti et al, 1995;Rocha and Infante, 1997;Volkering et al, 1998;Zhang and Miller, 1995). Many reports indicate that surfactants can enhance hydrocarbon biodegradation by increasing microbial accessibility to insoluble substrates (Zhang and Miller, 1994;Zhang et al, 1997).…”

“…Kastner et al (1998) showed that inoculation with a fluoranthene-degrading Sphingomonas strain and a pyrene-degrading Gordona strain resulted in no enhanced degradation of these PAHs, yet the strains survived well in the contaminated soil. Weir et al (1995) showed similar results with inoculation of a phenanthrenedegrading Pseudomonas strain that was encapsulated.…”

“…One approach for improving the effectiveness of bioaugmentation is to introduce the inoculum on an inert carrier. Immobilization or encapsulation has been shown to enhance survival and activity of the inoculum in bioremediation scenarios (Lin and Wang, 1991;Middledrop et al, 1990;Oh et al, 2000;O'Reilly and Crawford, 1989;Rhee et al, 1996;Weir et al, 1995). These studies used a variety of carriers including alginate, polyurethane foam and inert granular formulations.…”

Encapsulation of plant growth‐promoting bacteria in alginate beads enriched with humic acid

“…Moreover, alginate beads are capable of entrapping sufficient number of bacteria (Fenice et al, 2000;Zohar-Perez et al, 2002). The use of encapsulated cells for environmental applications has several advantages over free cell formulations namely, protection from biotic stresses (Smit et al, 1996) and abiotic stresses such as the inhibitory effect of toxic compounds (Cassidy et al, 1997), enhanced survival and improved physiological activity (Weir et al, 1995), supply of encapsulated nutritional additives (Trevors et al, 1993), increased cell densities and preferential cell growth in various internal aerobic and anaerobic zones of encapsulating gel. The encapsulation technologies face the trade-off among several major considerations such as, mechanical stability, controlled release, environmentally responsive, biodegradable, and cost-effectiveness.…”

A review on plant growth promoting rhizobacteria acting as bioinoculants and their biological approach towards the production of sustainable agriculture

“…The gel-like matrix with its catalytic ability allows the cells to remain viable for longer duration. Moreover, alginate beads entraps sufficient number of bacteria (Zohar-Perez et al, 2002) which shows several advantages over free cell formulations like, it protects the bacteria from biotic stresses (Smit et al, 1996) and abiotic stresses such as the inhibitory effect of toxic compounds (Cassidy et al, 1997), enhanced survival and improved physiological activity (Weir et al, 1995), supply of encapsulated nutritional additives (Trevors et al, 1993), increased cell densities and preferential cell growth in various internal aerobic and anaerobic zones of encapsulating gel. This technology was firstly used to encapsulate the plant-beneficial bacteria like A. brasilense and P. fluorescens (Bashan, 1986), which were later successfully used to inoculate wheat plants under field conditions.…”