Diversity of bacteria contaminating paper machines

Abstract

Formation of microbial biofilms and slimes is a general and serious problem in the operation of paper machines. Studies of microbial populations in paper machine-derived biofilms have been conducted using standard microbiological procedures; however, the bacterial genera present in this type of samples as well as their diversity are quite poorly known. Here, the bacterial diversity of 38 process water and 22 biofilm samples from four different Finnish paper machines were analyzed by length heterogeneity analysis of PCR-amplified 16S ribosomal DNA (LH-PCR). In addition, sequencing of the amplified 16S rRNA gene from 69 clones was conducted for characterization of the bacterial genera present in biofilm and slime samples. The LH-PCR profiles of both the free-living (process waters) and immobilized (biofilms) bacteria were diverse at all stages of the papermaking process. Out of the 69 sequenced clones, 44 belonged to alpha-Proteobacteria, most of which were close to the nitrogen-fixing root nodule genera Sinorhizobium, Rhizobium and Azorhizobium. Other clones were assigned to beta- and gamma-Proteobacteria and the phylum Bacteroidetes. In addition, eight of the clones were assigned to a yet uncultivated phylum, TM7. Finally, epifluorescence microscopy revealed that Gram-negative bacteria were predominant in both the biofilm (65%) and process water (54%) samples and a small coccoid cell morphology was most common in all samples. Together, our results show that the analysis of microbial samples from paper machines using modern molecular biology techniques adds valuable information and should, therefore, be useful as a more specific and sensitive microbiological method for the paper industry. This information could further be applied, e.g., in the development of more specific and environmental friendly antimicrobial agents for paper mills.

Bacterial Community Characterization in Paper Mill White Water

“…Scientific literature on the analysis of bacterial communities within the different compartments of a paper mill is nowadays scanty, especially when considering cultureindependent approaches (Tiirola et al 2009, Lahtinen et al 2006, Granhall et al 2010, Rasimus et al 2011). The majority of available studies have adopted culture-dependent techniques (Desjardins and Beaulieu 2003, Kolari 2003, Kolari et al 2003, Suihko et al 2004, Suihko and Skyttä 2009, thus underestimating the microbial diversity of the original sample.…”

“…To control bacterial proliferation in paper mills, the preferred strategy involves the use of chemical biocides, despite their high costs (Blanco et al 1996;Lahtinen et al 2006) and environmental impact. Biocides can be divided in oxidative and non-oxidative, and both types are used (Pauly 2002;Kiuru et al 2010aKiuru et al , 2010b.…”

Comparison of the Bacterial Microbiota in a Bale of Collected Cardboard Determined by 454 Pyrosequencing and Clone Library

“…In addition, biofilms were also studied by microscopy [5] [9] [10] [12], physiological and biochemical characterization [9] [10] [12], and fatty acids analysis [10] [12]. Unculturable bacterial population diversity has been determined in the fiber slurry [13] [14], white water [14] and biofilms [13]- [15] by 16S rRNA gene sequences.…”

New Tool To Monitor Biofilm Growth in Industrial Process Waters

“…The presence of biofilm in an industrial system causes biocorrosion and / or biofouling due to the formation of deposits. Paper mills suffer very often biofouling and biocorrosion problems, especially recycling paper mills, because along with the recovered paper used as raw material a vast array of microorganisms [4][5][6] enters a warm and nutritious environment 7 . In addition, the trend towards closing water circuits drives paper mills to work at process conditions that favour the growth of microorganisms, since the re-use of process water implies an increase in temperature and in the concentrations of dissolved organic material.…”