A comparative analysis of microflora during biofilm development on grape seeds exposed to methanol in a biofilter

Abstract

The attachment of microorganisms onto biotic surfaces to form biofilm structures on the support media of a biofilter has great impact on biodegradation systems. This study examined the composition of the microbial community that developed on grape seeds (GS) used as support media in methanol degradation biofilters. They were analyzed using conventional microbiology techniques and API galleries. Analysis of microbial counts showed that, in GS before methanol exposure, bacteria and filamentous fungi were predominant over yeasts. In contrast, GS exposed to methanol exhibited more bacteria and yeasts than fungi. Most of the Gram-negative bacteria were the Pseudomonas genus, Bacillus staerothermophilus, Bacillus amyloliquefaciens, and Bacillus pumilus. Rhodotorula mucilaginosa was the primary yeast found. The filamentous fungi Aspergillus sp. Cladosporium cladosporioides, Fusarium sp., and Alternaria sp. were also detected. No Gram-positive bacteria growth was found on GS exposed to methanol. Using scanning electron microscopy, biofilm formation on the GS was examined to reveal the presence of both prokaryotic and eukaryotic microorganisms as biomass accumulation was visible on the seeds. Seeds exposed to methanol for 90 days showed a mature biofilm with cuticle and epidermal layer decline, as well as biofilm dissolution into grape seed integuments.

Biofiltration of high concentrations of methanol vapors: removal performance, carbon balance and microbial and fly populations

“…Fifteen microorganisms were detected in the methanol biofilter (11 bacteria, three fungi, and one yeast, Table ). Such diversity is within the range observed in the literature . It is worth noting that for some species, several genetic variants have been isolated and identified, corresponding to different GenBank accession numbers.…”

“…Among them, one is strictly aerobic ( B. siralis ), while the others are facultative anaerobic. Bacillus species have already been observed in biofilters treating VOCs, including methanol . Nevertheless, this is the first identification of B. siralis in a biofilter.…”

“…Members of the proteobacteria phylum, dominant in biofilters, were detected, specifically two gammaproteobacteria of the Pseudomonas genus ( Pseudomonas sp., Pseudomonas mendocina ), and two alphaproteobacteria ( Pannonibacter phragmitetus , Caenispirillum bisanense ). Pseudomonas are common in biofiltration studies, and particularly while treating methanol ( Pseudomonas fluorescens , Pseudomonas putida , Pseudomonas cepacia , Pseudomonas mesophilica , and Pseudomonas vesicular ), but not Pseudomonas mendocina . Alphaproteobacteria, which can represent more than 10% of the biofilter population, have already been identified in methanol biofilters, but not the present species, as Pannonibacter and Caenispirillum genus have recently been isolated.…”

Industrial waste water for biotechnological reduction of aldehyde emissions from wood products

“…It is known that members of the bacterial genus Pseudomonas are efficient in metabolising wood extractives such as fatty acids (Burnes et al 2000;Kallioinen et al 2003). Pseudomonas species also have the potential to degrade VOC such as natural monoterpenes or toluene in biofiltration systems (Harder and Probian 1995;Mirpuri et al 1996;Kleinheinz et al 1999;Villaverde and Fernandez-Polanco 1999;Moreno-Terrazas et al 2009). The identified genus Pseudomonas and the presence of a complex microbial consortium combining various nutritious preferences and degradation features seem to carry the potential to successfully remove UFA and thus reduce aldehyde emissions from the investigated wooden Table 4 Extractives analytics of wooden boards made of effluent treated (Site I, Site II) and untreated (control) pine wood strands.…”

“…Biofilms are ubiquitous in many aqueous and solid substrates and are supposed to also grow on effluents collected or stored in ponds or basins of industrial plants. Biofilms from these habitats are composed mainly of bacterial or fungal species, which may be adapted to growth on wooden substrates and utilisation of their extractives (Moreno-Terrazas et al 2009). …”