Patent WO-2019145865-A1 (WO)
Title: Process for the production of sugars from biomass derived from guayule plants
Inventor: RAMELLO STEFANO
IPC: C12P19/02
Filed: 2019-01-23
Abstract: Process for the production of sugars from biomass derived from guayule plants comprising placing an amount of said biomass (G2) (g) in contact with an amount of water (Gi) (g) and with at least one organic acid, and optionally at least one inorganic acid, obtaining a mixture, said at least one organic acid and said at least one inorganic acid optionally present being used in such amounts that the total moles of said at least one organic acid and said at least one inorganic acid optionally present (ηΐτστ) contained in said mixture are calculated according to the following equation (1 ): m TOT  = m 1  + m 2  (1) wherein mi and mz are defined according to the following equations (2) and (3), respectively: m 1  = R 1 . G 1  (2) m 2  = R 2  · G 2  (3) wherein: R 1  (mmol/g) is the ratio between a first amount of said at least one organic acid (mmol) and a first amount of said at least one inorganic acid (mmo!) optionally present and the amount of water Gi (g) used, Ri being between 0.06 mmol/g and 0.25 mmol/g, preferably between 0.09 mmol/g and 0.18 mmol/g, said first amount of said at least one organic acid (mmoi) and said first amount of said at least one inorganic acid (mmoi) optionally present being dependent upon the amount of water G 1  (g); - R 2  (mmo!/g) is: - in the absence of said at least one inorganic acid, the ratio between a second amount of said at least one organic acid (mmol) and the amount of biomass G 2  (g) used; or - in the presence of said at least one inorganic acid, the ratio between the sum of said second amount of said at least one organic acid (mmol) and of a second amount of said at least one inorganic acid (mmol) and the amount of biomass G2 (g) used; or in the presence of said second amount of said at least one inorganic acid (mmol) and in the absence of said second amount of said at least one organic acid (mmol), the ratio between said second amount of said at least one inorganic acid (mmol) and the amount of biomass G 2  (g) used; said second amount of said at least one organic acid (mmol) and said second amount of said at least one inorganic acid (mmol) being dependent upon the amount of biomass G 2  (g); R 2  being between 0.90 R (mmol/g) and 1.10 R (mmol/g), preferably between 0.95 R (mmol/g) and 1.05 R (mmol/g), R being determined by the following algorithm (4), said algorithm (4) being obtained through the following elementary operations: (i) preparing a volume V (I) of an aqueous solution of said at least one organic acid and of said at least one first amount of said at least one inorganic acid (mmol) optionally present, said aqueous solution having a pH (1)  lower than 7, preferably between 0.7 and 3; (ii) adding an amount of biomass Q (g), dried at 120°C for 15 hours, to the aqueous solution obtained in (i), said amount of biomass being preferably lower than or equal to 60% by weight, more preferably between 2% by weight and 40% by weight, with respect to the total weight of the mixture obtained; (iii) measuring the pH of the mixture obtained in (ii), said pH being referred to below as pH (2) ; (iv) determining R according to the foi!owing algorithm (4): R = (10 -PH (1) - 10- pH (2)). 1000. V/Q) (4) wherein pH (1) , pH (2) , V and Q have the same meanings as above, the above elementary operations being carried out at room temperature; provided that said at least one organic acid is present in an amount such that the R MINIMUM  ratio (mmol/g) defined according to the following equation (5): R MINIMUM  = m ORGANIC ACID /G 2  (5) wherein m ORGANIC ACID  are the mmol of organic acid present and G 2  has the same meaning as above, is higher than or equal to 0.20 mmol/g, preferably higher than or equal to 0,25 mmol/g and, if said at least one inorganic acid is present, said mmol of organic acid (moRGANic ACID) are present in an amount smaller than the sum of the two amounts of acid, that is the sum of the amount of inorganic acid (mmol) and of the amount of organic acid (mmoi), said sum corresponding to the total moles η τοτ  (mmol) as defined in equation (1 ) above. The sugars thus obtained may advantageously be used as sources of carbon in fermentation processes for the production of alcohols (e.g., ethanol, butanol), lipids, diols (e.g., 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol), or in chemical synthesis processes for the production of other intermediates or chemicals. Said alcohols and lipids may in turn advantageously be used in the production of biofuels (e.g., biodiesel or "Green Diesel"), which may be used as such or in blends with other automotive fuels, while said diols may be used in the production of products such as, for example, bio-butadiene, which may in turn be used in the production of rubbers (e.g., polybutadiene or its copolymers). Said uses are particularly important in the case of a biorefinery.