Hernández-Pérez Andrés Felipe, de Arruda Priscila Vaz, Felipe Maria das Graças de Almeida
Departamento de Biotecnologia, Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, São Paulo, Brazil.
Departamento de Biotecnologia, Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, São Paulo, Brazil.
Braz J Microbiol. 2016 Apr-Jun;47(2):489-96. doi: 10.1016/j.bjm.2016.01.019. Epub 2016 Mar 2.
Sugarcane straw has become an available lignocellulosic biomass since the progressive introduction of the non-burning harvest in Brazil. Besides keeping this biomass in the field, it can be used as a feedstock in thermochemical or biochemical conversion processes. This makes feasible its incorporation in a biorefinery, whose economic profitability could be supported by integrated production of low-value biofuels and high-value chemicals, e.g., xylitol, which has important industrial and clinical applications. Herein, biotechnological production of xylitol is presented as a possible route for the valorization of sugarcane straw and its incorporation in a biorefinery. Nutritional supplementation of the sugarcane straw hemicellulosic hydrolyzate as a function of initial oxygen availability was studied in batch fermentation of Candida guilliermondii FTI 20037. The nutritional supplementation conditions evaluated were: no supplementation; supplementation with (NH4)2SO4, and full supplementation with (NH4)2SO4, rice bran extract and CaCl2·2H2O. Experiments were performed at pH 5.5, 30°C, 200rpm, for 48h in 125mL Erlenmeyer flasks containing either 25 or 50mL of medium in order to vary initial oxygen availability. Without supplementation, complete consumption of glucose and partial consumption of xylose were observed. In this condition the maximum xylitol yield (0.67gg(-1)) was obtained under reduced initial oxygen availability. Nutritional supplementation increased xylose consumption and xylitol production by up to 200% and 240%, respectively. The maximum xylitol volumetric productivity (0.34gL(-1)h(-1)) was reached at full supplementation and increased initial oxygen availability. The results demonstrated a combined effect of nutritional supplementation and initial oxygen availability on xylitol production from sugarcane straw hemicellulosic hydrolyzate.
自从巴西逐步引入免烧收割技术以来,甘蔗秸秆已成为一种可用的木质纤维素生物质。除了将这种生物质保留在田间外,它还可以用作热化学或生物化学转化过程的原料。这使得将其纳入生物精炼厂成为可能,生物精炼厂的经济盈利能力可以通过低价值生物燃料和高价值化学品(如具有重要工业和临床应用的木糖醇)的综合生产来支持。在此,木糖醇的生物技术生产被视为甘蔗秸秆增值及其纳入生物精炼厂的一条可能途径。在季也蒙毕赤酵母FTI 20037的分批发酵中,研究了作为初始氧可用性函数的甘蔗秸秆半纤维素水解产物的营养补充情况。评估的营养补充条件为:不补充;补充硫酸铵;以及用硫酸铵、米糠提取物和二水氯化钙进行完全补充。实验在pH 5.5、30°C、200rpm条件下,在125mL锥形瓶中进行48小时,锥形瓶中含有25或50mL培养基,以改变初始氧可用性。不补充时,观察到葡萄糖完全消耗和木糖部分消耗。在此条件下,在初始氧可用性降低的情况下获得了最大木糖醇产量(0.67 g g⁻¹)。营养补充分别使木糖消耗量和木糖醇产量提高了200%和240%。在完全补充和初始氧可用性增加的情况下,达到了最大木糖醇体积生产率(0.34 g L⁻¹ h⁻¹)。结果表明,营养补充和初始氧可用性对甘蔗秸秆半纤维素水解产物生产木糖醇具有联合作用。