Hiroshi Shimizu

An on-line physiological state recognition system for the lysine fermentation process based on a metabolic reaction model

A metabolic reaction model was developed for the lysine fermentation process by Corynebacterium glutamicum AJ-3462 to estimate the physiological state of the cells-that is, the growth and production activity, and the flux distribution of metabolites-from on-line measurable rates only. First, the extended Kalman filter was applied to eliminate noise in the measured rates. Then, using the metabolic reaction model, the lysine production rate and flux distribution were calculated. The estimation results allowed the physiological state of lysine production to be recognized, and an appropriate measure corresponding to the estimated state, such as intermittent addition of glucose and/or leucine, to be taken to maintain a high level of lysine productivity in batch culture. Finally, application of the recognition system enabled lysine to be produced from glucose at a higher yield than that from glucose- or leucine-limited exponential fed-batch cultures.

Synthesis of α-keto esters by the rhodium-catalysed reaction of cyanoformate with arylboronic acids

An arylrhodium(I) species selectively reacts with the cyano group of ethyl cyanoformate to afford the corresponding alpha-keto ester in good yield.

Day light quality affects the night-break response in the short-day plant chrysanthemum, suggesting differential phytochrome-mediated regulation of flowering.

Chrysanthemum (Chrysanthemum morifolium) is a short-day plant, which flowers when the night length is longer than a critical minimum. Flowering is effectively inhibited when the required long-night phase is interrupted by a short period of exposure to red light (night break; NB). The reversal of this inhibition by subsequent exposure to far-red (FR) light indicates the involvement of phytochromes in the flowering response. Here, we elucidated the role of light quality in photoperiodic regulation of chrysanthemum flowering, by applying a range of different conditions. Flowering was consistently observed under short days with white light (W-SD), SD with monochromatic red light (R-SD), or SD with monochromatic blue light (B-SD). For W-SD, NB with monochromatic red light (NB-R) was most effective in inhibiting flowering, while NB with monochromatic blue light (NB-B) and NB with far-red light (NB-FR) caused little inhibition. In contrast, for B-SD, flowering was strongly inhibited by NB-B and NB-FR. However, when B-SD was supplemented with monochromatic red light (B+R-SD), no inhibition by NB-B and NB-FR was observed. Furthermore, the inhibitory effect of NB-B following B-SD was partially reversed by subsequent exposure to a FR light pulse. The conditions B-SD/NB-B (no flowering) and B+R-SD/NB-B (flowering) similarly affected the expression of circadian clock-related genes. However, only the former combination suppressed expression of the chrysanthemum orthologue of FLOWERING LOCUS T (CmFTL3). Our results suggest the involvement of at least 2 distinct phytochrome responses in the flowering response of chrysanthemum. Furthermore, it appears that the light quality supplied during the daily photoperiod affects the light quality required for effective NB.

Profile control of the specific growth rate in fed-batch experiments

SummaryThe aim of this paper is to apply a computer control scheme to a laboratory scale fermentor so that the specific growth rate in a bakers yeast fed-batch culture, which cannot be measured directly, will follow as accurately as possible the desired profile specified in advance. Using an extended Kalman filter and programmed controller/feedback compensator (PF) system proposed previously, profile control of the specific growth rate (μ) was achieved experimentally in a bakers yeast fed-batch culture. Also, bang-bang type profile control of μ minimized the proportion of budding cells, which have a strong correlation with the fermentative activity in bread-making.

Identification of Fluorescent Substance in Mandarin Orange Skin for Machine Vision System to Detect Rotten Citrus Fruits

As basic research to develop a machine vision system to detect rotten mandarin orange, the extraction and identification of fluorescent substances contained in rotten parts of mandarin orange were conducted, and the excitation and fluorescence wavelengths of the substance were determined. Although it has been reported that damaged orange fruit skins are often fluoresced by UV light, it was suggested that fluorescent substances exist not only in the rotten parts of skins but also the normal parts of skins from this research. The fluorescent substances were extracted from 1kg of mandarin peel, and NMR analysis and mass spectrometry were conducted. From this experiment, it was found that the fluorescent substance was quite possibly heptamethylflavone and that the excitation and fluorescent wavelengths of one of the substances were 360 to 375nm and 530 to 550nm, respectively.

Light Environment Optimization for Lettuce Growth in Plant Factory

Abstract Plant factory is a crop production system which is isolated from outside environment. Fluorescent lamp is popularly used in the plant factory, however, the spectrum of fluorescent light is broad and some portion of them is not necessary for photosynthesis. On the other hand, LED (light emitting diode) has narrow band width and is getting common these days. The final goal of this project was to develop a new light apparatus with LEDs optimized for vegetable production in plant factory. The specific objective was to investigate the effective light quality for growing plant more healthy and rapidly. The effect of light provided by various light qualities provided by the combination of LEDs(blue, green, red) on the photosynthesis rate, growth and morphogenesis of lettuce (Lactuca sativa L “Greenwave”.) were evaluated and the response compared with those of plant irradiated by fluorescent lamps. Photosynthesis rate of lettuce was greater in monochromic red light and the mixed light with red and blue LEDs. Stem length increased in monochromic red and blue light and decreased in mixed light. Fresh weight of lettuce was increased in monochromic red and fluorescent light.

Model predictive controller for biodegradable polyhydroxyalkanoate production in fed-batch culture

The aim of this study is to develop a model predictive controller (MPC) accompanied with a metabolic reaction model controller for controlling ethanol and n-pentanol concentrations and the mole fraction of monomer units in the production of poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate), P(HB-co-HV), a biodegradable copolyester. The controller consists of two parts: one is for alcohol concentration control and the other one is for mole fraction control, and is based on the concept of metabolic flux distribution control. For control of alcohol concentration, conventional proportional and integral (PI) controller and feedforward/feedback controller did not function sufficiently because the large sampling interval of the biosensor led to a severe overshoot of concentration. A single-input and single-output (SISO) MPC is constructed for control of ethanol concentration in the growth phase, whereas a multi-input and multi-output (MIMO) MPC is constructed for control of both alcohol concentrations in the production phase. Specific ethanol consumption rate was estimated by the MPC using the past time series data of ethanol concentration. By means of simulations and experiments, the weighting parameters of the noise filters in the MPC were well adjusted. Ethanol and n-pentanol concentrations were well controlled by the MPC, compared with PI controller and feedforward/feedback controller. As a result, P(HB-co-HV) production was maximized with a given value of mole fraction of 3HV units at the end of cultivation.

Electro-hydraulic tillage depth control system for rotary implements mounted on agricultural tractor Design and response experiments of control system

A tillage depth control system for rotary implements mounted on an agricultural tractor was designed and constructed to improve accuracy of tillage depth. The control system was composed of five main units: (1) a detecting unit to measure the tilting angle (position) of the lift arm, the pitching angle of the tractor and heights of sensors from ground surface, (2) a controlling unit, (3) a hydraulic unit to operate a three-point hitch linkage by a lift arm cylinder, (4) a three-point hitch linkage and rotary implements, and (5) a setting unit to put the reference tillage depth and a dead zone into the control circuit. The tillage depth was controlled by an on/off operation of a solenoid valve, of which time was proportional to the controlling time. Experiments to evaluate the response characteristics of the control system were conducted under various engine speeds, i.e. various flow rates of hydraulic oil, various tillage depths and some input frequencies. The results of the response experiments of the control system are discussed in this paper.

End-of-day far-red treatment enhances responsiveness to gibberellins and promotes stem extension in chrysanthemum

SUMMARY A brief end-of-day (EOD) far-red (FR) exposure promotes extension growth in plants. This change suggests a role for gibberellins (GA). For chrysanthemum (Chrysanthemum morifolium Ramat.), we show that EOD-FR exposure enhances shoot extension and is mediated, at least in part, by increased responsiveness (sensitivity) to GA. In addition, our analysis showed how light, especially EOD-FR, influenced shoot extension. The effect of EOD-FR on promoting extension growth was maintained, not only during the dark period, but also in the subsequent light period. Furthermore, our observations suggest that dark reversion of certain phytochromes is involved in the determination of flowering time. We also discuss the applicability of EOD-FR treatment to reduce the overall duration of cultivation, while maintaining a sufficient stem height during cut chrysanthemum production.

Non-contact sensors for distance measurement from ground surface

Abstract Optical and ultrasonic sensors were designed and fabricated for non-contact detection of ground height. Indoor and outdoor experiments were conducted to evaluate the detection performance of both sensors under the following test conditions: moisture content and type of soil; ambient temperature and sunlight intensity; configuration of the ground surface; distance of the sensor from the ground surface; and moving speed of the sensor. The type of soil, the sunlight intensity and the moving speed had little effect on the detection performance of both sensors. The optical sensor could detect the distance from the ground surface accurately in spite of irregularity of the ground surface configuration. High moisture content (40% D.B.) of the soil greatly affected the detection performance of the optical sensor due to the refraction of the light at the water film on the soil surface. On the other hand, the detection performance of the ultrasonic sensor was not affected by moisture content, but was largely influenced by temperature. The detection accuracy of the ultrasonic sensor on an irregular ground surface was greatly affected by the measuring distance due to its wide beam width.