Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for "consolidated bioprocessing" (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.

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Microbial cellulose utilization: fundamentals and biotechnology.

Polyphasic taxonomy, a consensus approach to bacterial systematics.

Probiotic bacteria: safety, functional and technological properties

Lactic acid bacteria of foods and their current taxonomy.

Factors affecting the fermentative lactic acid production from renewable resources1

Summary: Lactobacillus plantarum strain 4B2, which exhibits a strong autoaggregating phenotype, receives the broad-host-range plasmid pAMβ1 with conjugation efficiencies as high as 10-2 transconjugants per donor using solid matings; broth matings also occur, but at low transfer frequencies. Filter-sterilized spent supernatant of this strain contains a 32 kDa protein that promotes aggregation, and consequently a high frequency of conjugation, in lactic acid bacteria containing α-1,2-glucose-substituted lipoteichoic or teichoic acids. It appears, therefore, that the substituted lipoteichoic or teichoic acids act as receptors for the aggregation-promoting protein.

/pdf/high-frequency-of-conjugation-in-lactobacillus-mediated-by-lszvxwb4ym.pdf

High frequency of conjugation in Lactobacillus mediated by an aggregation-promoting factor

Sixteen strains of Lactobacillus reuteri and 20 strains of Lactobacillus acidophilus were tested for resistance to 22 antibiotics by using commercially available sensitivity disks. Evidence suggesting linkage of these resistances to plasmids was obtained by "curing" experiments with acridine dyes and high growth temperatures. Examination of plasmid patterns of agarose gel electrophoresis provided further evidence of loss in plasmid DNA under curing conditions in some of the strains examined.

https://aem.asm.org/content/aem/43/1/50.full.pdf

Drug resistance plasmids in Lactobacillus acidophilus and Lactobacillus reuteri.

The deoxyribonucleic acid (DNA) relationship among Lactobacillus species of the subgenus Streptobacterium Orla-Jensen was assessed by means of DNA/DNA hybridization experiments. High genetic homologies were found among Lactobacillus casei subsp. casei, L. casei subsp. alactosus, L. casei subsp. pseudoplantarum, and L. casei subsp. tolerans; however, there was only a low level of homology between the DNA of L. casei subsp. rhamnosus and the DNA of other subspecies of L. casei. The DNAs of Lactobacterium zeae ATCC 15820 and L. casei subsp. casei ATCC 393 were nearly completely homologous. Although the latter strain has been proposed as the neotype for L. casei, it is not related to any of the other strains within the subspecies of L. casei. Lactobacillus plantarum and strains identified as belonging to L. plantarum subsp. rudensis and L. plantarum subsp. arabinosus formed a fairly homogeneous and easily recognized group. The DNA of Lactobacillus pentosus was unrelated to that of any known streptobacteria, and we therefore advocate the recognition of this organism as an independent species. There is a high degree of homology between Lactobacillus sake and Lactobacillus homohiochi; the name L. sake has priority, and L. homohiochi is very probably a synonym; for the same reason, Lactobacillus yamanashiensis has priority over its later subjective synonym, Lactobacillus mali. The general DNA/DNA homology relationships among Lactobacillus casei, L. plantarum, L. coryniformis, L. curvatus, L. xylosus, L. alimentarius, L. farciminis, and Sporolactobacillus inulinus justify their status as separate species.

Deoxyribonucleic Acid Homology Among Lactobacillus Species of the Subgenus Streptobacterium Orla-Jensen

The development of communities of the thermophilic microflora of natural whey culture for Parmigiano Reggiano cheese production was studied by means of molecular techniques. RAPD analysis facilitates the identification of the Lactobacillus strains involved in this microbial association and permitted the study of population dynamics during two cycles of whey fermentation. Analysis of RAPD fingerprints revealed the presence of four biotypes that dominate the whey fermentation process. Sequence analysis of 16S rDNA demonstrated that the strains isolated from whey belong to Lact. helveticus and Lact. delbrueckii ssp. lactis species.

Use of RAPD and 16S rDNA sequencing for the study of Lactobacillus population dynamics in natural whey culture

Topical pharmaceutical compositions, suited for the use in gynecology and urology, comprise as active principles selected Lactobacillus strains isolated from vaginal or urologic habitat of asymptomatic patients.

V. Bottazzi

Papers

High frequency of conjugation in Lactobacillus mediated by an aggregation-promoting factor

Drug resistance plasmids in Lactobacillus acidophilus and Lactobacillus reuteri.

Deoxyribonucleic Acid Homology Among Lactobacillus Species of the Subgenus Streptobacterium Orla-Jensen

Use of RAPD and 16S rDNA sequencing for the study of Lactobacillus population dynamics in natural whey culture

Pharmaceutical compositions comprising selected lactobacillus strains