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Abstracts of the Articles Printed in Seibutsu-kogaku Kaishi

Vol. 81. No. 3 (2003)

Influence of Resin-Adsorption as Pre-Treatment on Performance in Anaerobic Followed by Aerobic Treatments of Synthetic Textile Wastewater. SHIGERU MORIMURA,‘* TORU SHIGEMATSU,’ YASUTAKA Gwro,’ KEISUKE HAMADA,’ TAKAMASA NONAKA,’ KOUHEI TANEMURA,’ and KENJI KIDA’ (Department of Applied Chemistry and Biochemistry. Faculty of Engineering, Kumamoto University, 2-39-l Kurokami. Kumamoto 8604’555, I Department of Bioengineering, Yatsushiro National College of Technology, 2627 Hirayama-shinmachi, Yatsu- shire, Kumamoto 866~8501*) Seibutsu-kogaku 81: 95-103. 2003.

An anaerobic treatment of synthetic textile wastewater was carried out using a UAF (uvflow anaerobic filter) reactor. When the TOC volumitric loading rate was increased to 0.5 gl-’ d ‘, a residue of surfactant and volatile fatty acids was observed in the effluent. This was due to the inhibitory effect of the surfactant and dyes on the activity of aceticlastic methanogens. The wastewater was next subjected to a test of adsorption with the anion-exchange resin PCS-TEA, which was prepared from used trays and cups made of foam polystyrene. Only surfactant and dyes with sulfonate groups were adsorbed by PCS-TEA, which was ineffective against PVA, starch, and glucose. Another sample of synthetic textile wastewater, freshly prepared to correspond to the analytical values of the supernatant from the adsorption tests, was anaerobically treated in the same manner. Even at a TOC volumetric loading rate of 2.5 g I-’ d-t (HRT, 4.8 h), organic matter (starch and glucose) other than PVA was completely decomposed, and gas evolution yield was 0.17 1 (g TOC consumed)-‘. The color of the effluent was pale blue and the color index only 43”. The anaerobically treated effluent was subjected to aerobic treatment using a fluidized bed reactor at a TOC volumetric loading rate of 0.31 gt’ d-’ (HRT, I d). The decomposition efftciency of PVA was 97% and the eftlu- ent was colorless and clear with a color index of 17”.

* Corresponding author.

Molecular Mechanism of Polyphosphate Accumulation in Bacteria and Its Application - Monograph -. AKIO KURODA (Department qf Molecular Biotechnology, Gruduatr School qf Advanced Sciences qf Matter, Hiroshima Universiv,. PRESTO, JST l-3-1 Kagamivama, Hiroshima 739-8530) Seibutsu- kogaku81: 104-111.2003.

Inorganic polyphosphate (polyp) is a long chain of many hun- dreds of phosphate residues linked by high-energy phosphoanhydride bonds. Polyp is found in every living thing. Recently, it was revealed that polyp is involved in stationary phase regulation and stress re- sponses in bacteria. Here I describe (I) the molecular mechanism of polyp accumulation in Escherichia coli, (2) a physiological function of polyP in response to amino acid starvation, (3) a method for the isola- tion of polyP-accumulating mutants, (4) the development of a method for recovering polyp from polyP-accumulating bacteria, and (5) the discovery of a strictly polyP-utilizing glucokinase. We found that polyP accumulates in response to amino acid starvation in E. co/i. When E. coli is starved of amino acids, a Lon protease forms a com- plex with polyp with a binding constant of 0.5 nM and this complex degrades essential ribosomal proteins. Thus, polyp may reduce the general ribosomal function in a starving cell and provide amino acids from the degraded ribosomal proteins for the synthesis of proteins es- sential for adaptations during amino acid starvation. The biological

process for phosphorus removal from wastewater is based on the use of bacteria capable of accumulating polyp. We found that a phoU mu- tation leads to polyp accumulation in many bacteria. Polyp granules can be released from cells simply by heating them at 70°C for one to two hours. The polyp can be easily precipitated by the addition of cal- cium chloride without pH control. A pilot-plant-scale wastewater treatment system coupled with a process for polyp recovery showed high-level and stable performance for phosphorus recycling. We dis- covered a strictly polyp-utilizing glucokinase in a recently identified polyP-accumulating bacterium, Microlunatus phosphovorus.

Development of Ultra-High-Density Culture System for Mass Pro- duction of a Zooplankton Rotifer as Larval Fish Food by Control- ling the Dissolved Oxygen Concentration - Monograph -. KENJI TANAKA,‘* KENJI YOSHIMURA,* and TAKAO YosHIMATsti’ (Department of Biological and Environmental Chemistry, Kyushu School of Engineering, Kinki University. Iizuka, Fukuoka 820-8555. ’ Fukuoka Mariculture Corporation, Genkai, Munakata, Fukuoka 8I I- 3512.’ Lahoratorv of Advanced Animal and Marine Bioresources. Graduate School qf Biaresource and Bioenvironmental Sciences Kvushu University, Hakozaki. Fukuoka. 8/2-858/j) Seibutsu-kogaku 81: 112-l 17.2003

In recent years, the production of larval fish has been rapidly in- creasing worldwide. A zooplankton, the rotifer Brachianus ratundifor- mis, plays a very important role as the food of many marine larval fishes used in mariculture and fish cultivation. A typical mariculture corporation requires about IO billion rotifers every day. However, the culture density of rotifers in the conventional culture method was only ca. 200 individuals (ind.)/ml, which meant large culture tanks of over hundred tons capacity were essential for the production of enough roti- fers. Hence, we developed a high-density culture method incorporating the ideas and techniques of microbial engineering. First, condensed freshwater Chlorella were employed as new food for rotifers instead of the bakery yeast and marine Chlorella used in the conventional culture method. Second, we demonstrated that mechanical agitation, a high aeration rate, and the use of a tine porous sparger to attain a high k,,a were rather inhibitory to rotifer growth. Hence, the feeding of O2 gas was essential to avoid oxygen deficiency. Third, we found that main- taining the pH at 7.0 by automatic addition of HCI to promote the dis- sociation of NH, to NH,- and OH was very useful in reducing inhibi- tion by NH,. Fourth, a filtration unit was fitted in the culture tank to re- move waste matter from the culture liquid. IJsing these techniques, the culture density of rotifer increased to 20,000 ind./ml. Our high-density culture method is now being used by many mariculture corporations in Japan. Recently, we developed a novel culture system using a continu- ous membrane filtration unit (CMFU) for ultra-high-density culture. In this culture system, NH,’ and soluble organic substances, which can be nutrients for bacteria, are removed from the culture liquid. Using the CMFU, the rotifer density increased to 160,000 ind./ml and the popu- lation of Khrio sp. inhabiting in the rotifer body decreased to I /I 00,000 of that of a culture without CMFl 1. This new culture system is expected to have great potential for the mass production of sterile rotifer using a culture tank smaller than 100 I capacity.

* Corresponding author.

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