High Cellulose Production Research Articles

Optimization of microbial consortia and materials composition enhances gluconic acid content in kombucha.

The objective of this study was to optimize the microbial and ingredient composition of kombucha for enhanced production of gluconic acid (GA). Fourteen strains of Komagataeibacter spp. and one yeast strain of Dekkera sp. were isolated from kombucha. Among them, Komagataeibacter swingsii SS1 (SS1) and Komagataeibacter saccharivorans SS11 (SS11) were selected for their high GA production. A rapid reduction of pH, high GA content relative to acetic acid, and high cellulose production were observed in the tea infusion fermented by the microbial consortium (SS1 + SS11 + Dekkera bruxellensis Y24). From the correlation between the materials composition and quality indicators of kombucha, the decrease in pH was the most critical quality indicator of kombucha and the most closely related to GA content. Maximal GA production (11.7mg/mL) was obtained under the conditions of 1% (w/v) tea extract, 8.5% (w/v) glucose, and 1.5% (v/v) ethanol through the optimization of materials composition by response surface methodology. The GA content of kombucha was enhanced threefold in comparison to general kombucha by fermentation with Komagataeibacter spp. and optimization of the composition of the ingredients. Overall, this study showed that a specific microbial consortium and materials composition could be established by correlation analysis among the ingredients, which results in increased GA levels in kombucha. These findings offer valuable foundational data for both commercial production and quality control of kombucha.

ZmPGIP1 regulates stem strength by enhancing lignin and cellulose biosynthesis in Arabidopsis thaliana

Polygalacturonase inhibiting proteins (PGIPs) are typical leucine-rich repeat (LRR) proteins that inhibit the activity of polygalacturonase (PG) in pathogens, but their function in promoting to plant stem development has been less studied. In this study, the PGIP gene from Zea mays was cloned and heterologously expressed in Arabidopsis thaliana, and then the plant phenotypes were observed and a set of physiological and biochemical indicators were measured. The results indicate that the ZmPGIP1 protein is expressed both in the cell membrane and cell wall. Our research observed that the heterologous expression of ZmPGIP1 significantly increased the production of lignin, cellulose and hemicellulose in transgenic lines. The stems of transgenic plants also showed a thicker cortical tissue. The increase in lignin deposition observed during histochemical staining suggests that the ZmPGIP1 gene may improve plant mechanical strength. These were tightly associated with the upregulated expression of lignin/cellulose-synthesis genes (C4H, C3H, F5H, PAL1/3, CCR1, CAD1-3/9, CCOMT, MYB58, CESA1/10) to enhance plant cell wall strength in transgenic lines. Our findings provide new perspectives on the growth regulation mechanisms of PGIP proteins in plant cell walls and provide a potential candidate gene for breeding increased disease-resistance and higher cellulose production in plants.

Bacterial cellulose: A highly versatile nanomaterial.

Bacterial cellulose: A highly versatile nanomaterial.

Bio-conversion of kitchen waste into bacterial cellulose using a new multiple carbon utilizing Komagataeibacter rhaeticus: Fermentation profiles and genome-wide analysis

A cellulose-producing bacterium Komagataeibacter rhaeticus K15 was isolated from kombucha tea, and its metabolic pathways and cellulose synthesis operon were analyzed by genome sequencing. Different from the reported K. rhaeticus, the K15 produced little gluconic acid (2.26 g/L) when glucose was the sole carbon source and has the capacity for high cellulose production (4.76 g/L) with other carbon sources. Furthermore, six nitrogen-fixing genes were found to be responsible for the survival of K15 on a nitrogen-free medium. Based on its fermentation characteristics, K15 was cultured in a kitchen waste medium as a strategy for green and sustainable bacterial cellulose production. The SEM, XRD, and FTIR results indicated that synthesized cellulose has a mean diameter of 40–50 nm nanofiber, good crystallinity, and the same chemical structure. The K15 strain provides a highly viable alternative strategy to reduce the costs of bacterial cellulose production using agro-industrial residues as nutrient sources.

By-products of the cider production: an alternative source of nutrients to produce bacterial cellulose

In the present work a culture process to produce bacterial cellulose (BC) using by-products of the cider production from the Basque Country was investigated. The apple pomace was mixed with sugar cane (AR/SC medium) and the mixture was found to be a potential carbon source for Gluconacetobacter medellinensis strain ID13488 since higher cellulose production was observed with respect to the commercial Hestrin and Shramm medium (H–S). The culture media were characterized in terms of pH, oxygen and sugars consumption. The expression level of the operon bcs (genes involved in BC biosynthesis) in apple residue containing medium respect to standard H–S medium was determined. It was found that in AR/SC medium the expression levels of bcsA gene, wich is the first gene of the bcs operon, was increased in 1.5-fold respect to the H–S media which correlates with the fact that BC production in AR/SC media is higher than in H–S media. The physico-chemical and mechanical properties, microstructure, crystallinity and water holding capacity of the biosynthesized BC membranes were analyzed and it was found that, in general, the BC obtained from AR/SC medium presented superior properties than that obtained from H–S medium. In this study an economic method for BC production is proposed with suitable properties for many applications.

Overview of Bacterial Cellulose Production and Application

Abstract Bacterial cellulose (BC), produced by aerobic bacteria received ample of attention due to its unique physiochemical properties compared to plant cellulose. Intense researches on BC mainly focus on biosynthetic process to achieve low-cost preparation and high cellulose production. BC has been used as biomaterial for medical field, electrical instrument and food ingredient. However, BC alone has limited capabilities to fulfil current demand on high-performance biomaterials. Hence, BC composite has been introduced to enhance BC properties through addition of reinforcement materials. This review discusses current knowledge in fermentation process and potential application of BC including its application in food industry.

Virulence characteristics of food processing relevance in isolates of Listeria monocytogenes and Escherichia coli 0157: H7 strains isolated from 'wara' a West African soft cheese

Three strains of Escherichia coli 0157:H7 and eleven strains of Listeria monocytogenes isolated from West African wara cheese were analysed for cellulose production, fimbriae formation, zetapotential and biofilm formation which are of relevance in food processing. E. coli c produced no fimbria, very low cellulose and significantly lower zetapotential (-3.1) among the three strains. The L. monocytogenes (b) had the highest zetapotential (-39.1) and cellulose production at 24 h of incubation. Next to it was L. monocytogenes (f) which also had a higher cellulose production at 72 h incubation. A positive correlation exists between zetapotential and cellulose production in the E. coli strains (R2 = 0.67) while Listeria monocytogenes strains gave a negative correlation (R2 = -0.08). There was no significant difference in biofilm formation in the L. monocytogenes strains (P < 0.05), however the L. monocytogenes (a) had the highest at 48 h incubation. Weak positive correlation (R²) values of 0.0397, 0.002 and 0.0011 were obtained for 24, 48 and 72 h incubation for Listeria monocytogenescounts (cfu/ml) and cellulose measurements. This study further accentuate and confirmed the presence of E. coli and L. monocytogenes with virulent factors that of relevance to the method of processing in West African soft cheese. The need for an improved hygiene during processing and sale of this product to prevent the transmission of these pathogenic organisms to humans is therefore emphasized. Key words: West African soft cheese, Escherichia coli, Listeria monocytogenes,virulent strains

Utilization of d-xylose as carbon source for production of bacterial cellulose

Utilization of d-xylose as carbon source for production of bacterial cellulose was studied. Seventeen strains of acetic acid bacteria were screened for their cellulose productivity in d-glucose, d-xylose, and d-xylose/ d-xylulose mixed media, respectively. d-Xylose was not well metabolized by any bacterial strains that exhibited high cellulose production in d-glucose medium. Consequently, bacterial cellulose production in d-xylose medium was unsuccessful. d-Xylose, however, became utilizable substrate for bacterial strains if xylose-isomerase was added to the medium. Acetobacter xylinus IFO 15606 was the best cellulose producer in d-xylose/ d-xylulose mixed medium, so cultural conditions were studied for enhanced cellulose production. With pH controlled, the strain could produce cellulose at a yield exceeding 0.3 g per 100 ml of d-xylose/ d-xylulose mixed medium, which was comparable to the yields in d-glucose medium by excellent producers in the literature.

Screening of Bacterial Cellulose-producingAcetobacterStrains Suitable for Sucrose as a Carbon Source

For potential application in the economic production of bacterial cellulose, cellulose-producing Acetobacter strains capable of using sucrose as a carbon source were screened for using corn steep liquor as a nitrogen source. A total of 1500 strains were isolated and four were selected through static and shaking flask cultures. Much higher cellulose accumulation was observed in a jar fermentor using these strains in sucrose-CSL medium than seen using the previously isolated strain, BPR2001, in fructose-CSL medium. It was found that these strains also had high cellulose production from glucose. The pH of the cultures of the isolated strains did not decrease, and it was suggested that these strains have low glucose-oxidizing ability.

High Rate Production in Static Culture of Bacterial Cellulose from Sucrose by a Newly IsolatedAcetobacterStrain

For the industrial production of bacterial cellulose from sucrose in static cultures, the possibility of a high rate of cellulose production was investigated. An Acetobacter strain, S-35, which had been isolated from a grape, was selected from 1500 isolates. This strain was found to produce a large amount of cellulose from either glucose or fructose. Using this strain, high cellulose production rates of 3.3g/liter/d or 40g/m2/d from sucrose were seen in static culture.

A Synthetic Medium for Bacterial Cellulose Production byAcetobacter xylinumsubsp.sucrofermentans

Of several organic nitrogen sources tested, corn steep liquor (CSL) was found to be the most suitable for cellulose production by Acetobacter xylinum subsp. sucrofermentans BPR 2001. When lactate, which was detected only in CSL, was added to culture media containing other nitrogen sources, cellulose production was stimulated to levels similar to that in CSL medium. Lactate was found to stimulate cell growth during the early stage of culture and shown to function by linking with the respiratory chain and generating energy for growth. Therefore, it was speculated that lactate acts as an accelerator driving the TCA cycle as well as an energy producer, resulting in high cellulose production and rapid cell growth. The effects of various amino acids were also investigated: L-methionine was found to be essential for high cellulose yields and stimulation of cell growth during the early stage of culture. On the basis of these observations, a defined synthetic medium, containing lactate and methionine, was formulated, with which cellulose production of 90% of that with the CSL medium was reached in jar fermentor cultures.

High Bacterial Cellulose Production by Acetobacter xylinum ATCC 10245 in a New Culture Medium with a Sulfite Pulping Waste Fraction.

Higher cellulose production was observed in a new culture medium (named KC medium) consisting of a sulfite pulping waste fraction (named CP powder), glucose, yeast extract, peptone and buffer components as compared with the standard 2% glucose Hestrin-Schramm culture medium (HS medium). Acetobacter xylinum ATCC 10245 cultivated in KC meduim of 2% glucose gave high cellulose yields (296%), and the highest yield was obtained at the 3% dosage of glucose and 0.5% dosage of the CP powder (326%). The fractionation and the ion exchange experiments suggested that the high molecular lignosulfonate contributed to the yield enhancement.

Plasma-membrane rosettes involved in localized wall thickening during xylem vessel formation of Lepidium sativum L.

Developing xylem vessel elements in roots of cress, Lepidium sativum L., were freeze-fractured after rapid freezing in nitrogen slush (without cryoprotection). With the double-replica technique, both the plasmatic fracture face (PF) and the extraplasmatic fracture face (EF) of the plasma membrane were exposed. The EF revealed abundant, but rather indistinct "terminal globules"; whereas the PF showed numerous "rosettes". Terminal globules and rosettes were localized, restricted to regions of secondary wall thickening only, and showed comparale frequencies per μm(2), supporting the assumption that they are part of the same synthase complex. The abundance of rosettes in regions of high cellulose production supports their postulated involvement in cellulose microfibril formation. With up to 191 rosettes per μm(2), the rosettes appear to be too densely arranged to be directly aligned on individual microtubules. This favors the channelling hypothesis of synthase movement in the plasma membrane.