Biomedical subjects

Yoshitoshi Nakamura

Publications and source records attributed to Yoshitoshi Nakamura.

4 recordsLinked to original sources

PubMed2005

Bioconversion of lignocellulosic waste from selected dumping sites in Dar es Salaam, Tanzania.

The poor management of solid wastes in Tanzania urban centers is a chronic problem that has increasingly become a source of environmental pollution. Bioconversion offers a cheap and safe method of not only disposing these wastes, but also it has the potential to convert lignocellulosic wastes into usable forms such as reducing sugars that could be used as food. This paper reports a preliminary study on the physical characteristics, acid pretreatment, saccharification by cellulase from Trichoderma reesei and fermentation by Saccharomyces cerevisiae of the lignocellulosic component of the solid wastes collected from various dumping sites located in Kinondoni Municipality, Dar es Salaam city. The results showed that overall, the lignocellulosic component constitute about 50% of solid wastes dumped in the study areas. Maximum production of reducing sugars was obtained after 6h of saccharification while highest concentrations of bioethanol were achieved after 48 h of fermentation. Microbial bioconversion of lignocellulose component yielded up to 21% bioethanol.

Biodegradation, Environmental↗

PubMed2005

Determination of Cu, Pb, Fe, and Zn in plant component polymers of a hyperaccumulating plant.

Phytoremediation is an innovative technology that utilizes the natural properties of plants to remediate hazardous waste sites. For more cost-effective phytoremediation, it is important to utilize a hyperaccumulating plant after phytoremediation, i.e. the recovery of valuable metals and the production of useful materials. In this work, the determination of metals in plant component polymers in a fern, Athyrium yokoscense, as a hyper-accumulating plant was established using steam explosion, Wayman's extraction method, and ICP emission spectrometry. After A. yokoscense plants were treated by steam explosion, the steam-exploded A. yokoscense were separated into four plant component polymers, ie. water-soluble material fraction, holocellulose fraction, methanol-soluble lignin fraction, and residual lignin fraction. The concentrations of Cu, Pb, Fe, and Zn in these plant component polymers and the dry weights of plant component polymers were measured. These analytical process determining metals in the plants will contribute to not only the evaluation and the efforts of phytoremediation using a hyperaccumulating plant, but also to the development of more effective phytoremediation.

Biopolymers↗

PubMed2004

Methane production from steam-exploded bamboo.

To convert unutilized plant biomass into a useful energy source, methane production from bamboo was investigated using a steam explosion pretreatment. Methane could not be produced from raw bamboo but methane production was enhanced by steam explosion. The maximum amount of methane produced, i.e., about 215 ml, was obtained from 1 g of exploded bamboo at a steam pressure of 3.53 MPa and a steaming time of 5 min. A negative correlation between the amount of methane produced and the amount of Klason lignin was observed in the methane fermentation of steam-exploded bamboo.

Journal Article↗

PubMed2003

Efficient production by Escherichia coli of recombinant protein using salting-out effect protecting against proteolytic degradation.

To produce glucoamylase efficiently as a recombinant protein, E. coli was grown with 20 g (NH4)2SO4 l-1 which removed proteolytic activity but did not effect cell growth. Growth in M9 medium with 20 g (NH4)2SO4 l-1 produced 11 U glucoamylase ml-1 compared to 7 U ml-1 without addition. Furthermore, the glucoamylase activity was maintained at about 9 U ml-1.

Ammonium Sulfate↗