生物煉製（Biorefinery）泛指利用生質物提煉生質燃料或生物特用化學品，為近年來重點開發的技術，其中利用農林廢棄物中的木質纖維素之煉製技術更是積極開發的項目。本研究嘗試利用台灣地區常見的農業廢棄物甘蔗渣的木質纖維素作為原料，使用黑曲黴(Aspergillus niger)進行液態發酵產檸檬酸。 由於直接使用未處理之甘蔗渣做為碳源利用效果並不佳，藉由稀酸水解法可將甘蔗渣中半纖維素水解釋放出可利用之單醣。另外進行二次酸水解可以提高醣濃度，然而對微生物具有抑制現象的有害物質乙酸、5-羥甲基糠醛(HMF)以及糠醛(Furfural)等亦隨之提升，其中乙酸及5-羥甲基糠醛(HMF)已達到抑制菌體生長濃度值，為主要抑制菌體生長的有害物質。本研究採取活性碳吸附處理方式進行這類有害物質之移除，經過移除後的酸水解液可成功的進行檸檬酸發酵生產，其中檸檬酸的最大產量與組成培養基所建構對照組相較之下可達78％（酸水解液：9.3 g/L對照組：11.77 g/L），且比生長速率亦相近（酸水解液：0.075；對照組：0.083）。 Biorefinery, which is one of the renewable technologies, has been developed for few years. And the use of lignocellulosic materials available in agricultural wastes as a source of raw material for citric acid is interest because of their renewable nature and abundance. The present study discusses the hydrolysate of sugar cane bagasse as carbon source for the production of citric acid by Aspergillus niger . First, we use sugar cane bagasse in medium directly, but the results show that it was not a good method. Then we use dilute acid method for sugar cane bagasse pretreatment, which is one of the few technologies to break down the protective structure of lignin and hemicellulose, but during pretreatment process, several compounds like acetic acid and 5-hydromethylfurfural and furfural were toxic to microorganisms. However, there need some methods to detoxify the acid hydrolysates. In this study toxic compounds were removal from hydrolysate by activated charcoal, so that the hydrolysate could be used by A. niger .After detoxic process, the maximum growth rate (μmax) and citric acid concentration of A.niger fermentation were closed to those of the control medium.
