Bacterial community diversity in paper mills processing recycled paper

Paper mills processing recycled paper suffer from biofouling causing problems both in the mill and final product. The total bacterial community composition and identification of specific taxa in the process water and biofilms at the stock preparation and paper machine areas in a mill with recycled paper pulp was described by using a DNA-based approach. Process water in a similar mill was also analyzed to investigate if general trends can be found between mills and over time. Bacterial community profiles, analyzed by terminal-restriction fragment length polymorphism (T-RFLP), in process water showed that the dominant peaks in the profiles were similar between the two mills, although the overall composition was unique for each mill. When comparing process water and biofilm at different locations within one of the mills, we observed a separation according to location and sample type, with the biofilm from the paper machine being most different. 16S rRNA gene clone libraries were generated and 404 clones were screened by RFLP analysis. Grouping of RFLP patterns confirmed that the biofilm from the paper machine was most different. A total of 99 clones representing all RFLP patterns were analyzed, resulting in sequences recovered from nine bacterial phyla, including two candidate phyla. Bacteroidetes represented 45% and Actinobacteria 23% of all the clones. Sequences with similarity to organisms implicated in biofouling, like Chryseobacterium spp. and Brevundimonas spp., were recovered from all samples even though the mill had no process problems during sampling, suggesting that they are part of the natural paper mill community. Moreover, many sequences showed little homology to as yet uncultivated bacteria implying that paper mills are interesting for isolation of new organisms, as well as for bioprospecting.     

Biotech paper watch

Biotech paper watch: From our sister journals Special issue on Lipidomics Most accessed in BTJ: IgCAM neuronal cell adhesion molecules BioEssays Other publications     

Biotech paper watch

BioEssays Reviews From our sister journals Most downloaded from the BTJ double issue 9/10 Other publications New on the market     

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BTJ best cover contest Biotech paper watch: Triple knockout cell lines in one go Turning carbon dioxide into liquid fuel Dual malaria/cholera vaccines from chloroplast Automated single cell clone picking Disulfide trapping of yeast surface proteins pH changes upon freezing of buffered solutions Identifying cancerspecific glycosylation p53, a double-edged sword in the fight against cancer Most read in BTJ: SUMOylation and cell signalling Bioengineering news: Biofuels for future generations Textile wastewater decolorization Engineering joint cartilage     

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From our sister journals Most accessed in BTJ November 2008 Best cover in 2008 BioEssays Other publications     

Description of heterotrophic bacteria occurring in paper mills and paper products

AIMS: To isolate aerobic mesophilic bacilli and thermophilic bacteria from different paper mill samples and to evaluate their potential harmfulness. METHODS AND RESULTS: A total of 109 mesophilic and 68 thermophilic isolates were purified and characterized by automated ribotyping and partial 16S rDNA sequencing. The mesophilic isolates belonged to the genera Bacillus (13 taxa), Brevibacillus (three taxa) and Paenibacillus (five taxa). The thermophilic bacteria represented seven taxa of Bacillus, Geobacillus or Paenibacillus, four of proteobacteria and one of actinobacteria. The most frequently occurring bacteria were Bacillus cereus, B. licheniformis, Pseudoxanthomonas taiwanensis and bacteria closely related to Paenibacillus stellifer, P. turicensis or Leptothrix sp. One mill was contaminated throughout with bacteria of a novel mesophilic genus most closely related to Brevibacillus centrosporus and another with bacteria of a novel thermophilic genus most closely related to Hydrogenophilus thermoluteolus. One B. cereus isolate producing haemolytic diarrhoeal enterotoxin was detected and all the tested B. licheniformis isolates produced a metabolite toxic to boar sperm cells. CONCLUSIONS: The bacilli and thermophilic bacteria isolated represent species which should not present occupational hazards in paper mill environments. The most harmful bacterium detected was B. licheniformis and potentially also B. cereus. SIGNIFICANCE AND IMPACT OF THE STUDY: Knowledge of the microbial diversity in a paper mill provides a rational basis for development of an effective controlling programme. A database constructed from the fingerprints generated using automated ribotyping helps to identify and trace the contamination routes of bacteria occurring in paper mills.     

A review of anaerobic digestion of paper and paper board waste

Paper and paper board (PPB) products represent one the largest fractions of municipal solid waste. PPB are mainly composed of lignin, cellulose, and hemicellulose (lignocellulose). Previous research has shown that the anaerobic digestion (AD) of unprocessed lignocellulosic materials is limited by the occurrence of lignin. Additionally, it is well known that removal of lignin improves AD of unprocessed lignocellulosic materials. Unlike unprocessed lignocellulosic materials, PPB are subjected to a series of mechanical and chemical processes during their fabrication, which may have an effect on the AD of PPB. This review aims to (1) summarize the AD of PPB with respect to the compositional and structural changes caused by the papermaking process; (2) evaluate the results of technologies that have been applied to increase the degradability of PPB; and (3) discuss the current and future challenges that involve the AD of PPB. The data analyzed in this review revealed that lignin content only explains 56% of variation in PPB methane yields. Consequently, other properties affected by paper-making processes most likely also influence their AD. Codigestion and pretreatment are potential alternatives to improve AD of PPB. However, to achieve further improvement, research is needed to identify and quantify the non-compositional properties that dictate degradability, and to develop pretreatment processes that can target the rate/yield limiting properties precisely.