244 



CARBOHYDRATES AND GLUCOSIDES 



[154. 



154. Dextrose; d-Glucose; 



Grape Sugar ; Starch Sugar ; 



Hexanepentolal. 



HO H HO HO 

 CHO C C C C CH 2 . OH 



H HO H 



H 



NATURAL SOURCES. 



"Widely distributed throughout the 

 vegetable kingdom, being found in the 

 sap of plants and in most fruits and 

 flowers. It is generally accompanied 

 by Isevulose and sometimes by certain 

 C 12 -sugars, especially saccharose. 



Honey contains from 32 to 42 per 

 cent, of dextrose (Dubrunfaut and Sou- 

 beiran, Jahresber. 1849, 464 ; Roeders, 

 Ibid. 1863,574; Brown/ Analyst/ 1 87 8, 

 257 : see also Konig and Karsch, Zeit. 

 anal. Ch. 34, I ; Beckmann, Ibid. 35, 

 263 ; v. Raumer, Ibid. 41, 333). 



Manna, an exudation from the manna 

 ash (Ornus europcea and 0. rotundifolia), 

 contains from 2-3 per cent, of dextrose 

 (Tanret, Bull. Soc. [3] 27, 947). 



A honey-like exudation from Euony- 

 mus japonica, produced by insect punc- 

 tures, contains dextrose (Maquenne, 

 Bull. Soc. [3] 21, 1082). 



The sugar from mahwa-flowers from 

 Bassia latifolia consists of l invert sugar' 

 (v. Lippmann, Ber. 35, 1448). 



Crocin and picrocrocin from the saf- 

 fron plant, Crocus saliva, contain the 

 dextrose complex (Kastner, Ch. Centr. 

 1902, 2, 383). 



The natural products known as gluco- 

 sides, which are found in such large 

 numbers of plants, are esters, in which 

 generally some sugar, and most fre- 

 quently glucose, plays the part of 

 a polyhydric alcohol (see BeilstehVs 

 ' Handbuch/ III, 565, and ' Die Glyko- 

 side' by Van Rijn, Berlin, 1900). 



Saccharose (cane-sugar) is resolved 

 by the majority of yeasts into dextrose 

 and Isevulose. Moulds such as Asper- 

 gillus niger and Penicillium glaucum 

 exert the same action (Gayon, Comp. 

 Rend. 86, 52 ; Duclaux, ' Chimie bio- 

 logique/ 1883; Fernbach, These, 1890 : 

 for two last see J. R. Green's ' Fer- 

 mentation/ p. 1 15). 



Penicillium duclanxi as well as P. 

 glaucum can invert cane-sugar (Bour- 

 quelot ; J. R. Green, luc. cit.}. Monilia 

 Candida can also hydrolyse saccharose 

 (Fischer and Lindner, Ber. 28, 3037). 

 Mucor racemosus is said to be capable 

 of inverting saccharose (Fitz, Ber. 17, 

 1196 ; Brefeld, Landw. Jahrb. 5, 308, 

 as quoted by Fitz). Saccharose is not 

 hydrolysed by Saccliaromyces apiculatus 

 (Fischer and Lindner, loc. cit. 3039). 



Monilia javanica, one of the fungi 

 present in the ferment ' raggi ' used 

 for preparing arrack in Java (see under 

 ethyl alcohol [14]), can invert saccharose 

 (Went and Prinsen Geerligs, Bot. Zeit. 

 1895, p. 143). The ferment ' koji ' used 

 in Japan for preparing 'sake' is also 

 capable of inverting saccharose (Kellner, 

 Mori, and Nagaoka, Zeit. physiol. Ch. 

 14, 297 ; Kozai, Centr. Bakter. II, 6, 



385). 



The enzymes of various yeasts, &c., 

 which are capable or incapable of 

 hydrolysing polysaccharides have been 

 investigated by Kalanthar (Zeit. physiol. 

 Ch. 26, 88). 



Certain bacteria (Clostridium, Clado- 

 thrix, and Sarcina] are capable of invert- 

 ing saccharose (Laxa, Centr. Bakter. II, 

 6, 286; Ch. Centr. 1900, 1, 1298). 

 This sugar is inverted in bouillon by 

 Bacillus megatherium, B. jiuorescens 

 liquefaciens, and Proteus vulgaris (Fermi 

 and Montesano, Centr. Bakter. II, 1, 

 482; 542; Ch. Centr. 1895, 2, 712). 

 The sugar Bacteria of Marshall Ward 

 and J. R. Green can invert saccharose 

 (Proc. Roy. Soc. 65, 79). So also can 

 the gum-producing Bacillus levani- 

 formans (Greig- Smith and Steel, Journ. 

 Soc. Ch. Ind. 21, 1381) and the sugar- 

 gelatinising Clostridium gelatinosum 

 (Laxa, Zeit. Zuekerind. 26, 122 ; Journ. 

 Fed. Inst. 8, 639). Streptococcus hornen- 

 sis probably inverts saccharose (Boek- 

 hout, Centr. Bakter. II, 6, 161). 



Maltose is fermentable only by those 

 yeasts which contain the enzyme malt- 

 ase (Sacch. cerevisite and octosporus), and 

 not by those containing invertin (Sacck. 

 marxianus}. It is thus probable that 

 the hydrolysis of maltose to dextrose 

 precedes fermentation (Fischer, Ber. 28, 

 1433 : see also Maquenne's work for 



