Kazuhiko Sameshima

Enhancement of growth and cellulose accumulation by overexpression of xyloglucanase in poplar

Because the loosening of xyloglucan in the cell wall promotes plant growth (Takeda et al. (2002) Proc. Natl. Acad. Sci. USA 99, 9055–9060; Park et al. (2003) Plant J. 33, 1099–1106), we expressed Aspergillus xyloglucanase constitutively in Populus alba. The expression increased the length of stem even in the presence of sucrose. Increased stem growth was accompanied by a decrease in Youngs elastic modulus in the growth zone but an increased elasticity in mature tissue. The increased internode length corresponded to an increase in cellulose content as well as specific gravity, showing that the removal of xyloglucan might cause an increase in cellulose density in the secondary xylem.

The utilization of sugar cane molasses with/without the presence of lignosulfonate for the production of bacterial cellulose.

Production of bacterial cellulose (BC) using sugar cane molasses (MO) with/without the presence of lignosulfonate (MOL) as a sole carbon source in a Hestrin–Schramm medium (HS) was investigated. Six strains of Acetobacter xylinum [American Type Culture Collection 10245 and Institute of Fermentation in Osaka (IFO) 13693, 13772, 13773, 14815, and 15237] were screened for their BC production. The yield of the BC among all the strains from both the MO and MOL media was much higher than that from the HS medium. Acetobacter xylinum IFO 13772 was the best BC producer for all media. Furthermore, physical properties of these BC from the HS, MO, and MOL media were studied using Fourier-transform infrared spectroscopy, X-ray diffractometer, and cross polarization/magic angle spinning 13C nuclear magnetic resonance. There are no significant differences in the crystallinity and the recorded Iα fraction among the BC produced from the different media. A remarkable difference was only recorded in terms of viscosity. These results indicate that MO is a better carbon source than glucose for most of the strains investigated.

Identification and genetic relationships of kenaf (Hibiscus cannabinus L.) germplasm revealed by AFLP analysis

Kenaf (Hibiscus cannabinus L.) is one of the worlds most economically important fiber crops. In order to identify different varieties, and investigate its diversity and genetic relationships, twenty-three kenaf accessions and two accessions of its relative, roselle (H. sabdariffa var. altissima), were analyzed by morphological characterization and AFLP fingerprinting. It is very difficult to identify kenaf accessions based merely on morphological characters, due to their limited variation. For the AFLP study, a total of 505 polymorphic markers (out of 560) were produced by six selected AFLP primer combinations. The AFLP fingerprinting was effective in identifying all kenaf accessions included in the study. Kenaf and roselle are independent species with close relationships, and great genetic diversity was also detected among the kenaf accessions with different origins, based on the analysis of the AFLP markers. The AFLP analysis strongly supports the opinion that kenaf originated in Africa. It also demonstrated that the dissemination of kenaf was from Africa through Asia to Central and North America.

Combination treatment of kenaf bast fiber for high viscosity pulp

The viscosity of kenaf bast fiber has been found to be highly sensitive and variable with different pulping methods; therefore, it is important to choose proper chemicals and conditions for pulping and bleaching of kenaf bast fiber. From several pulping experiments, a nonconventional pulping method with a combination of ammonium oxalate pretreatment followed by soda pulping at normal pressure and then acidic chlorite delignification was developed to obtain high-viscosity pulp (162 centipoise). The optimum level of alkali dosage of soda pulping for high-viscosity pulp was found to be 15% (on pulp as NaOH). Pulps showed linear relations between viscosity and xylose or glucose contents, but the combination pulping method gave extremely high pulp viscosity, beyond the relations. The highest viscosity pulp from kenaf bast fiber demonstrated a tear index about twofold and a folding endurance 6.2-fold higher than those of Manila hemp pulp with comparable tensile and burst indexes. The high-viscosity pulp could be used in the production of high-quality currency paper or longevity paper for special uses.

Influence of the chemical composition of kenaf bast and core on the alkaline pulping response

The bast and core of kenaf,Hibiscus cannabinus L., have markedly different chemical components and alkaline cooking responses. The bast had about double the hot-water extractives content and only about half the lignin content of the core. The core contained a large amount of hemicellulose, mostly composed of xylan. The lignin structures of bast and core were also quite different: The former had a significant abundance of syringyl structures. Evidence showed that the bast was much more easily delignified than the core. When the bast and core were cooked together in alkaline condition, the pulp yields at the same kappa number were higher than those of the individual pulpings of bast and core. The bast-core pulping gave a positive effect on the yield of bast pulp in the sodaanthraquinone and kraft pulpings. On the other hand, kenaf was abundant in the hot water extractives. These extractives consumed alkali during cooking to a relatively large extent but acted as a protector of hemicellulose and slightly increased the pulp yields.

Anatomy and Properties of Japanese Hardwoods I. Variation of Fibre Dimensions and Tissue Proportions and their Relation to Basic Density

Variations of tissue proportions and fibre dimensions (fibre length, fibre cross sectional area, fibre wall thickness, fibre wall area, percentage of fibre wall area) of 50 Japanese hardwoods are compared. The fibre cross sectional area showed large variations as compared to fibre length. There is no significant correlation between fibre cross sectional area and fibre wall thickness.The multiple regression analysis showed that fibre wall thickness, percentage of fibre wall material and ray volume are the parameters most closely correlated with basic density.

A New Method of Sample Preparation for Kenaf Bast Fiber Length Analysis with Automated Fiber Length Analyzer

Summary Kenaf bast fiber bundles alternate radially in layers accompanied by sieve elements and phloem parenchyma cells. Fiber bundles are about 20 % in the area of a cross section of kenaf bast. Four sample preparation methods for kenaf bast fiber length analysis with an automated fiber length analyzer were compared and a new sample preparation method including three steps was proven to be accurate. Fiber bundles were obtained by acidified sodium chlorite treatment and an additional ammonium oxalate treatment. Following a 1% sodium hydroxide treatment, fiber bundles were completely separated into single fibers with no damage. Fiber length values of this method were more accurate and reliable than other three sample preparation methods and manual measurement with optical microscope.

Selection of plant population of kenaf (Hibiscus cannabinus L.) as a papermaking raw material on arid hillside land in China

Agronomic properties (whole stalk yield, fiber length distribution, chemical composition) and whole stalk kraft pulp characteristics (total pulp yield, pulp fiber length distribution, pulp sheet strengths) were examined for kenaf (variety Zhehong 8310) at four plant populations, ranging from 135 000 to 405 000 plants/ha on arid hillside land at Anji, Zhejiang, China. For agronomic properties, the final whole stalk yield was higher as the plant population increased and as the altitude of the location on the slope decreased. Average fiber lengths of bast and core showed maxima at 225 000 plants/ha. Cellulose content increased as the plant population increased. For the kraft pulp characteristics of kenaf whole stalk, the total pulp yield was lower as the plant population increased, with the maximum difference about 1.3%. Sheet strengths and average fiber length attained maxima at around 225000–315000 plants/ha. The largest pulp strengths (breaking length, burst index, and folding endurance) were seen at a plant population of 225000 plants/ha, and the largest tear index was seen at a plant population of 315 000 plants/ha. When the agronomic properties and whole stalk kraft pulp characteristics were combined, a plant population between 225 000 and 315 000 plants/ha, which is a little higher than that of kenaf bast production for textiles, was selected as the optimum cultivated kenaf plant population for whole stalk kraft pulp and papermaking on arid hillside land in China.