著者

北原 覺雄 村田 卯一

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.31, no.3, pp.90-98, 1953-03-15

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Experiments were carried out on the diastase systems of 124 strains of aspergilli, including 120 strains of flavus-Oryzae; 3 strains of awamori; and 1 strain of kawachii, isolated from commercial 'Tane-koji'-the starters for koji-making.1) Characteristics of flavus-Oryzae a) Generally, flavus-Oryzae is far superior to any other species of mold in α-amylase activity. And this will be the very reason what made possible the peculiar procedure of sake brewing, starting from the mash containing as high as 35% of starch.b) The difference of α-amylase activities, lying between the extreme strains of flavus-Oryzae, has been indicated as the ratio of 8 to 1,when compared with the time for disappearance of iodine color. Strains comparatively rich in α-amylase are used for industries manufacturing such as sake and spirits, while poorer strains are used for making 'shoyu'. Consequently, it appears probable that protease is inversely distributed among the strains against α-amylase. However, this problem is left for future studies.c) Maltase power of flavus-Oryzae is generally inferior to other mold species, but there exist several exceptional strains having quite strong maltase activities.d) No cor-relation can be seen between the activities of α-amylase and maltase, among the strains of flavus-Oryzae.e) Within the present exprimental conditions, maltase activity reveals maximum at the koji of 38 hrs incubation, and gradually declines by prolonged culture, but on the other hand α-amylase activity receives almost no effect by the age of koji. This functional change of maltase activity will be considered as one of the remarkable characteristics of flavus-Oryzae, since such phenomenon can hardly be seen in other species.(2) A simple enzyme-analysis a) Wheat-bran culture, which contains solely α-amylase, is readily obtainable when a voluntary strain of comparatively weak in maltase activity was cultured for eight days. This is an application of the phenomenon mentioned in the preceding article (e).b) Applying the treatment for eliminating α-amylase, it has been confirmed that flavus-Oryzae possesses an amylase of β-type. The β-amylase is most active when a strain having comparatively strong maltase activity was cultured for 38 hrs.c) At present, authors feel no inconsistency towards KITANO'S view of 'Taka-maltase', considering that β-typed amylase of flavus-Oryzae is combined with maltase activity, because the raise and fall of the β-amylase activity are quite parallel with those of maltase. Consequently, Taka-maltase (Asp. Oryzae) appears to be quite alike, even if it should not be identical. with gluc amylase (Rh. delemar) or amylo-glucosidase (Asp. niger), however, all of them have a question whether they can be made free from maltase, like γ-amylase.

著者

小玉,健吉

出版者

大阪醸造學會

雑誌

醗酵工學雑誌

巻号頁・発行日

vol.52, no.1, 1974-01-25

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A taxonomic survey has been made of ascosporogenous yeasts found in exudates occurring on tree stumps of broad-leaved trees in Japan during the periods of April and July of 1967,1968,1972,and 1973. The samples were collected in test tubes by using cotton pieces. Usually within 2 to 7 days after collecting, a loopful of the sample was streaked directly on carrot juice-koji extract agar medium containing 100 ppm of chloramphenicol. At the same time, samples were enriched by 2 kinds of liquid media besides the koji extract, i.e., sodium acetate-peptone-yeast extract, and glucose-nitrate media, both supplemented with 100 ppm of chloramphenicol, for 3-7 days at 25℃ followed by streaking on the agar media mentioned above. The pure cultures were identified mainly by the procedures described in "The Yeasts" edited by Lodder (1970). Out of 334 strains identified, this paper deals with the species belonging to the genera Saccharomyces, Schizosaccharomyces, Pichia, and Debaryomyces.Among these a new species of Pichia naganishii is proposed beased on the reasons menitioned below.Pichia naganishii Kodama sp. n.The strain studied resembles Pichia angophorae Miller et Barker and Pichia bovis van Uden et do Carmo-Sousa, in both the shape of the ascopore and the assimilation pattern of the routine five sugars.However, in contrast to P. angophorae, this strain does not form pseudomycelium, nor does it ferment sucrose and maltose but assimilates _L-arabinose, _D-ribose, _L-rhamnose, glycerol and erythritol, and can grow at 37℃. Also, this strain is differentiated from P. bovis, in that it assimilates in addition to the above carbon compounds, ribitol and galactitol, and furthermore heterogamous conjugation preceds its ascus formation.Single strain (LKB-747) of this species was isolated from exudate of Camellia sp. in Nagasaki prefecture.

著者

竹内 徳男 細川 信男 吉田 政次

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.50, no.1, pp.21-29, 1972-01-25

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The characteristics of proteolysate in 1) enzyme miso (E.M.) manufactured with only the protease preparation, Biosaime A, prepared from Aspergillus oryzae and 2) ordinary miso (O.M.) prepared by the usual method using koji were compared. Both E.M. and O.M. miso were manufactured with the same procedure except koji in O.M. was replaced with Biosaime A in E.M. 1. Liberated amino acid patterns in the defatted soybean flour with Biosaime A were virtually similar to that of free amino acid in E.M. 2. Free, bound and whole amino acid patterns of E.M. were not markedly different from that of O.M. This seems to indicate that the main effect of Biosaime A closely resembles the proteolytic action of koji. However, in the E.M., pyroglutamic acid and free arginine content were greater, on the contrary, aspartic acid and glutamic acid were less than those of O.M. It was suggested from the above results that Biosaime A is deficient in some enzymes, such as glutaminase and asparaginase. 3. Distributive patterns of peptides and their bound amino acid composition were fairly similar in the three types of miso, i.e., O.M., E.M. and half koji miso, examined. These results infer that the greater part of peptides originated from soybean protein and not from enzyme protein or microorganisms. Peptide content in miso were 25-29% (calcd. as amino acid) to whole amino acid, 20.6-24.2% (as nitrogen) to the total nitrogen and 30-34% (as nitrogen) to water soluble nitrogen, respectively. 4. Forms of glutamate in O.M. and E.M. miso were as follows : insoluble type 16-17 and 18% ; bound type about 40 and 36.5% ; free type 36-38 and 29.1% ; and pyroglutamic acid 4-7 and 16.3% respectively. 5. During the process miso-making, loss of amino acids was observed. The degree of loss, in order of magnitude was whole koji>half koji>E.M.

著者

根井 仁三郎

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.49, no.10, pp.852-860, 1971-10-25

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The effects of several physiological conditions on the phenol-oxidizing activity of a strain of Rhodotorula glutinis var. glutinis were studied.1. The maximum rate of phenol oxidation was shown in cells precultured on glucose with vigorous aeration, starved and induced by phenol.2. Of the carbon sources tested in the preculture medium, glucose and xylose resulted in high yields of cells and a high rate of phenol oxidation. The strain was capable of utilizing nitrate. Among the nitrogen sources surveyed in the medium, ammonium nitrate permitted a high rate of phenol oxidation. 3. Starvation for 12 hr was required for the development of a maximal rate of phenol decomposition. The presence of organic nitrogen enhanced the potential for induction, suggesting the repression of induction of phenol oxidation by sugars.4. The optimal pH for induction and phenol oxidation of the pretreated yeast cells was 5.5 and the optimal temperature was 34℃. The development of phenol-oxidizing activity was suppressed at temperatures below 25℃ and at pH levels above 8.5. With a decrease in the concentration of phenol in the induction medium, an increase in the rate of induction of phenol oxidation was observed. The maximal rate of phenol oxidation of the cells was obtained when 500 mg/l of phenol was added to the oxidation medium. The maximum rate of initial oxidation of phenol was observed at a concentration of 200 mg/l.6. The effect of several reagents on phenol oxidation by yeast was investigated. Sodium azide, cyanide, and formaldehyde, at a concentration of 2 mM, exerted 50 % inhibition. Of the chelating agents, o-phenanthroline and 8-hydroxyquinoline, at a concentration of 10 mM, inhibited oxidation of phenol by 72% and 40%, respectively.7. Rapid oxidation of phenol by induced cells was carried out in a jar fermenter. The cells decomposed phenol at concentrations of 2,000 mg/l and 3,000 mg/l in 5.5 hr and 16 hr, respectively. These results suggest a good possibility for the application of the yeast to the treatment of phenol in industrial waste..

著者

木暮,保五郎

出版者

大阪醸造學會

雑誌

醗酵工學雑誌

巻号頁・発行日

vol.35, no.12, 1957-12-15

著者

中山,大樹

出版者

大阪醸造學會

雑誌

醗酵工學雑誌

巻号頁・発行日

vol.43, no.3, 1965-03-25

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In the Kiso district of Nagao prefecutre, there is a local pickle called sunki, a native vegetable food, prepared without brine or vinegar. The author isolated 25 strains of lactic acid bacteria from 15 specimens of sunki and five specimens of various pickles, obtained from the same distric. In this paper 19 strains of isolated rods were identified as follows : - One strain of spore bearing rod isolated from dried sunki was identified as B. coagulans Hammer. Six strains of homo-fermentative rods were identified as L. plantarum (Orla-Jensen) Holland, one strain of hetero fermentative rods was identified as L. buchneri (Henneberg) Bergey et al, and 10 strains of hetero-fermentative rods L. brevis (Orla-Jensen) Bergey et al.Among these strains two strains can be considered as new varieties, for which the authors proposed the names of L. plantarum (Orla-Jensen) Holland var. sunkorum nov. var. and L. brevis (Orla-Jensen) Bergey et al. var. otakiensis nov. var. respectively.

著者

菅間,誠之助

出版者

大阪醸造學會

雑誌

醗酵工學雑誌

巻号頁・発行日

vol.52, no.9, 1974-09-25

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Commerically available take-koji, sporulated koji and used as the seed for koji making, is sometimes regarded as one of the sources of infection by lactic acid bacteria in sake brewing. To sterilize these contaminants by heat and, at the same time, to minimize the heat inactivation of Aspergillus oryzae conidiospores, the heat drying conditions of take-koji have been examined.1) The heat resistance of lactic acid bacteria was different depending on species and cultural age : Leusonostoc mesenterioides B-95 was more stable than Lactobacillus casei B-83,and in regard to the same species, the cells harvested from the culture at the maximum groeth were most stable (see Fig.1,Fig.2 and Table1). Therefore, Leuc. mesenteroides B-95 cells at the maximum growth was used for determination of the drying conditions.2) The patterns of thermal death of the test organisms on the surface of steamed rice or on tane-koji seemed to be related to the patterns of heat drying of solid materials : the velocity of thermal death in the constent rate period of drying was more rapid than that in the falling rate period. In the latter period, the spores of Asp. oryzae became very stable (see Table 2). In the drying of steamed rice, the critical moisture content was in the range from 0.15 to 0.20 H_2O per g dry stock.According to these results, a two steps method for drying of tane-koji, namely low temperature drying at constant rate period succeeded by high temprature drying at falling rate period, has been proposed. For example, in the case of the low temperaturedrying at 40℃(wet-bulb temperature)(t_w) : 28℃) for 3 hours and high temperature dryig at 60℃(t_w : 32℃) for 12 hours, the concentration of Leuc. mesenteroides diminished to 10^<-8> times the initial. Under these conditions, the rate of inactivtion of Asp. oryzae spores was only 10 per cent.

著者

河合 啓一 江口 良友

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.54, no.2, pp.128-130, 1976-02-25

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Lactobacillus buchneri IFO 3961の無細胞抽出液より, グルコース-6-リン酸脱水素酵素をブルーデキストラン-セファロース4Bを用いたアファニティクロマトグラフィーにより精製した.本酵素は低イオン強度条件下に.ブルーデキストラン-セフィロースに吸着され, 1mM NADPあるいは1M塩化カリウムを含む10mMリン酸カリウム緩衝液(pH7)にてほぼ定量的に溶出された.塩化カリウムを用いる直線的濃度勾配法により溶出したところ, 約80%の収率で比活性約120倍の酵素標品を得ることが出来た.本標品はpH9.4でのポリアクリルアミドゲルデイスク電気泳動により単一のバンドを示した.

著者

勝井,五一郎

出版者

大阪醸造學會

雑誌

醗酵工學雑誌

巻号頁・発行日

vol.28, no.7, 1950-07-15

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The following were the findings made through the investigation of 17 marine and 3 fresh-water fishes as regards the manner of distribution of Vitamin A. Those which contain a large amount of Vitamin A in livers are "Saba", "Buri", "Ishidai", "Ara", "Mejina", "Hokke", "Aburatsunozame", "Mebachi", "Makajiki", "Mekajiki" and "Ishinagi". Those which contain a large amount of Vitamin A in pyloric caecum are "Saba", "Buri", "Ara" and "Hokke". Those which contain a large amount of Vitamin A in intestines are "Buri" and "Ara". The above-mentioned are of great value as resources of Vitamin A, if we choose suitable seasons and places of fishing.

著者

東,修一郎

出版者

大阪醸造學會

雑誌

醗酵工學雑誌

巻号頁・発行日

vol.39, no.9, 1961-09-15

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In order to obtain a high yield of crystalline dextrose, second hydrol (the mother liquor from the second crystallization stage) was reconverted from which an additional crop of crystalline dextrose was obtained. Conditions for reconversion were established on the basis of the experimental results in small scale laboratory autoclaves. Later, a 150 l autoclave and a commericial batch converter as well as a continuous conveter were used for pilot plant trials. The optimum conditions for reconversion with batch converter were found to be acid (oxalic) concentration 0.04N, hydrol concentration Be10°, pressure 2kg/cm^2 and reaction time 20 minutes. With these conditions, second hrdrol having a DE (dextrose equivalent) of 73 and a DX (dextrose content based on dry substances) of 55 per cent was reconverted to a DE of 83 and a DX of 76 per cent, while the same hydrol was reconverted with continuous converter to a DE of 85 and a DX of 79 per cent. Yields of crystalline dextrose from reconverted liquors with batch and continuous converters were 27 per cent and 42 per cent (based on hydrol dry substances) respectively.

著者

小玉 健吉 京野 忠司 小玉 正次郎

出版者

大阪醸造學會

雑誌

醗酵工學雑誌

巻号頁・発行日

vol.35, no.11, 1957

著者

酒沢 千嘉弘 世古 洋康 市川 邦介 福井 三郎

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.42, no.10, pp.607-614, 1964-10-25

被引用文献数

1

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In a preceding paper, the fundamental conditions necessary in experiments employing the Warburg manometric technique to study the stimulatory effect of activated sludge on methane fermentation were discussed.In this paper, an attempt was made to isolate the stimulatory factors for gas production in methane fermentation from an aqueous extract of activated sludge. Fractionation of factors was carried out with Amberlite IR 120 resin, activated charcoal and paper chromatographic techniques. Results obtained showed the existence of at least three effective factors. The effects of activated sluge on methane fermentation seemed to be a complex one involving unidentified brownish colored substance as an essential factor and a group of amino acids and purine derivatives, such as adenine and hypoxanthine, as supplement factors.

著者

田口 久治 西村 公臣

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.29, no.3, pp.98-101, 1951-03-15

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I. Characters of Actinomyces No. M. 1. : At the beginning, an actinomyces which produces two kinds of antibiotic substances entirely different from streptomycin and streptothricin in biological and chemical respect, was isolated. This strain, No.M.1,resembles very closely A. alboflavus, and somewhat related with A.farcinicus and A.roseus in its biochemical characteristics.II. Production of the antibiotics in the broth : When the strain was grown under submerged culture in the medium containing 1% glycerine, 0.5% meat extract, 0.5% peptone, 0.5% NaCl, the antibiotic activity reached to 88 streptomycin units (using E. coli SIRAISI as the test organism), but when glycerine was replaced by glucose, dextrine or lactose, the potency was not very high. Starch was found suitable for hte production of the antibiotics, just in the same way as the glycerine (Table 1). The anitibiotics seem to be produced in an increased quantity in the medium containing 0.25% (NH_4)_2HPO_4,or 0.005% MgSO_4,and especially when 5% Nuka-extract was added, the antibiotic activity reached to 245 units (Table 2).III. Methods of extraction : (Fig.1)1) First method of preparing antibiotic substance : The filtrate is readily extracted by the use of ethyl acetate. Then the ethyl acetate solution is concentrated to its 1/5 volume by vacuum distillation.The concentrated ethyl acetate solution is passed through alumina column.The column may be washed by passing the mixture of ethyl acetate and ether (2 : 1) through it. At first, the yellow part of the liquid comes out of the bottom containing antibiotic substance. The solvnets in this fraction will be removed by vacuum distillation, yellow powder being deposited.This substance may be tentatively designated as M1-A.2) Secondary antibiotic substance : This second substance is extracted from the residual broth left after extraction of the first substance, in the same way as those used in the isolation of streptomycin and streptothricin. This substance may be tentatively called as M1-B.IV. Chemical properties : According to the color reaction of protein and amino acid, M1-A and M1-B are different from streptomycin and streptothricin, but when they are examined by the antibacterial spectrum, M1-B resembles closely streptothricin (Table 3,Table 4). The minimum lethal doses of M1-A and M1-B are 2mg and 1mg per 20g mice respectively.

著者

中山 大樹 小池 弘子

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.43, no.3, pp.157-164, 1965-03-25

被引用文献数

1

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In the Kiso district of Nagao prefecutre, there is a local pickle called sunki, a native vegetable food, prepared without brine or vinegar. The author isolated 25 strains of lactic acid bacteria from 15 specimens of sunki and five specimens of various pickles, obtained from the same distric. In this paper 19 strains of isolated rods were identified as follows : - One strain of spore bearing rod isolated from dried sunki was identified as B. coagulans Hammer. Six strains of homo-fermentative rods were identified as L. plantarum (Orla-Jensen) Holland, one strain of hetero fermentative rods was identified as L. buchneri (Henneberg) Bergey et al, and 10 strains of hetero-fermentative rods L. brevis (Orla-Jensen) Bergey et al.Among these strains two strains can be considered as new varieties, for which the authors proposed the names of L. plantarum (Orla-Jensen) Holland var. sunkorum nov. var. and L. brevis (Orla-Jensen) Bergey et al. var. otakiensis nov. var. respectively.

著者

川島 栄吉

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.51, no.1, pp.41-46, 1973

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A respiration-less of Saccharomyces was cultivated by the batch or the continuous method in a culture stirred fermenter with glucose as the limiting substrate. In the batch cluture, initial conditions had an important effect upon the characteristics of the lag phase. The inoculation of more cells, or more active cells, shortened the period of the lag pahse. Monod's equation could not explain the above experimental results. And so, a mathematical model for the microbial growth process aws presented on the assumption that the growth rate is controlled in two steps and the lag phase is represented Eqs. 1 to 7. The parameters involved in the above equations were estimated by certain experimental data. The activity of cell accounted by the intermediate drived from glucose in cell. On the other hand, for the continuous culture, substituting in these equations with the mass balance ezuations, two steady states were obtained for each dilution rate; one was stable and the other was unstable. It was suggested that continuous culture may tend to wash out under certain initial conditions, in spite of a lower dilution rate.

著者

松中

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.31, no.4, 1953-04-15

著者

福田 芳雄 原田 篤也 泉 美治

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.51, no.6, pp.393-397, 1973-06-25

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土壌中よりDL-α-ハイドロキシニトリルを唯一の窒素源として生育する酵母を分離し, まずこの菌株GN405の菌学的性質をLodderの方法によってしらべ, Torulopsis candidaの1菌株と同定した.この菌株は種々なニトリル化合物を唯一の炭素源として利用できなかったが, アセトニトリル, プロピオニトリル, ブチロニトリル, DL-α-ハイドロキシイソバレロニトリル, DL-α-ハイドロキシイソカプロニトリルを唯一の窒素源として利用できた.DL-α-ハイドロキシイソバレロニトリルを窒素源として生育した培地からの菌体を用いて, ハイドロキシニトリル化合物に作用させ, えた生産物の元素分析, 赤外吸収分析, 施光度および融点の測定を行なった.その結果DL-α-ハイドロキシイソバレロニトリルとDL-α-ハイドロキシイソカプロニトリルよりそれぞれえられたハイドロキシ酸はL-α-ハイドロキシイソバレリアン酸とL-α-ハイドロキシイソカプロン酸であることがわかった.この反応に関与する酵素は1種のニトリラーゼと考えられる.酵素は基質に対して誘導的に生成される.アミノニトリル化合物には作用しない.

著者

今中 忠行 海江田 豪児 田口 久治

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.51, no.6, pp.423-430, 1973-06-25

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前報で, 菌体増殖および酵素生産に関する動力学モデルを提出した.本報では, まずgalactose取り込みの制限条件を検討した結果, glucoseの添加によりgalactoseの細胞内への取りこみはon-off方式でただちに完全に阻害されること, およびgalactoseの細胞膜透過系は構成的であることが判明した.またこれらの事実より, 酵素誘導に長時間を要する主因は, galactoseの膜透過系にあるのではなく, 細胞内の諸反応と細胞内での物質移動であると考えられる.さらに本モデルを用いて酵素誘導とその抑制, glucoseとgalactoseを含む回分培養および連続培養の非定常過程の実験結果をすべて十分に説明すつことができた.以上のことから, 本モデルと解析に用いた諸定数を最適化の計算に用いる妥当性十分と判定した.

著者

照井 堯造 小林 連吉 寺本 四郎 上田 清基 合葉 修一 宮内 照勝 七字 三郎 河野 竹彦 安井 之雄 芝崎 勲 富金原 孝 三浦 喜温

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.43, no.3, pp.198-217, 1965-03-25

著者

熊 傑田 上田 誠之助

出版者

公益社団法人日本生物工学会

雑誌

醗酵工學雑誌 (ISSN:03675963)

巻号頁・発行日

vol.54, no.4, pp.241-248, 1976-04-25

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重質経由(high boiling point gas oil)を唯一の炭素源として40〜50℃を適温とする細胞, 酵母, 放射菌およびカビのスクリーニングを行った.得られた30株の中に9株の放射菌と1株のカビ以外に全部は細菌であった.細菌の中に普通によく知られている細菌よりリン含量が高い菌を数株分離した.その中の1株Brevibacteriumの一種であると同定した.A25R菌は石油資化性がよく, その菌体内リン酸化合物を分画して標準菌株と比べて見ると冷酸可溶画分とKOH可溶画分に特徴があることがわかった.冷酸可溶部を分画して見るとATPは 3.6μg/mg-cells, ADPは2.3μg/mg-cellsであった.KOH可溶画分中にRNAの分解に由来したモノヌクレオチッドのCMP, AMP, UMPとGMPのほかに氷冷した10%トリクロル酢酸で抽出できないが, アルカリによって分解をうけつつ抽出される糖のリン酸エステルが存在していることがわかった.このリン酸エステルの検討について後に報告する.Brevibacterium sp. A25R菌を用いてその培養条件を検討したところ, 有機窒素源は必要でなく, 無機塩と重質軽油でも培養できた.炭素源濃度を0.2〜10v%とかえても, つねに一定の比増殖速度0.35hr^<-1>をもつことがわかった.炭素源濃度が2v%以上では, 菌体濃が2〜3mg/mlを越えると資化できる炭化水素がまだ残っているのに, 増殖速度が減少しはじめ, 長時間にわたって低い速度で増殖しつづけることがわかった.この現象について2,3の検討を行った.培養の最初の5時間内にはpHの変動がなく, 中和剤の添加が見られなかったが, 培養が進むにつれてpHが酸性になり, 中和剤の添加が見られた.培養液のpHを6.4〜7.4にたもつために加えられた4N NaOHが不定形に変形した油滴を円形にもどすという現象が観察された.NaOH中和での油滴が円形にもどすため菌体の接触しうる油滴表面積が減り, 菌の増殖が不良になったのではないかと推察した.一方, 4M(NH_4)_2HPO_4で中和する場合, 変形した油的が培養が進むにつれて更に小さくなっていて対数増殖期(始発炭素源濃度が4v%の場合)は菌体濃度7〜8mg/ml までつづき, 最大菌体濃度は8mg/mlに達すること(NaOHで中和する場合は 5.6mg/mlであった)がわかった.更に0.06%Tween60を含む4M(NH_4)_2HPO_4で中和する場合, 油滴は4M(NH_4)_2HPO_4だけで中和する倍より更に細かい変形油的になり, 菌体濃度は 9mg/mlまで高めることができた.このように中和剤の油滴形状や大きさへの影響は大きく, それらが菌体増殖へ強く作用することが認められ, 石油醗酵の場合油滴を細かく培養液中に分散させる手段とか, 菌の乳化力を妨害する因子の回避を考慮に入れなければならないと思う.