In April 2011, biomass group (http://brg.groups.xtbg.ac.cn/) in Xishuangbanna Tropical Botanical Garden (XTBG), CAS reported their new progress in biodiesel production and conversion of by-product glycerol to high-value-added products. Related results were published in the international journal “Bioresource Technology” (http://dx.doi.org/10.1016/j.biortech.2011.04.007), and filed a patent.

Biodiesel is an environment-friendly and renewable fuel, which is regarded as one of the excellent alternatives for conventional diesel fuel from petroleum industry. The screening and utilizing of high-active and recyclable new catalysts for biodiesel research has gained much attention. However, with the development of biodiesel production, excessive glycerol is produced as by-product. Hence, the conversion of glycerol to high-value-added products should be studied. Under the guidance of Professor Zhen Fang and Dr. Feng Guo, PhD student Yunduo Long found a new route for the co-production of biodiesel and lactic acid based on large number of experiments, which included a transesterification of triglycerides and a hydrothermal degradation of by-product glycerol catalyzed by solid sodium silicate. The results demonstrated that crude plant oil could be converted into biodiesel with the yield of up to 99.6% through catalytic transesterification over calcined sodium silicate. The catalyst was cycled for 6 times. Then, as the activity of catalyst declined, the reused catalyst was collected through centrifugation, and applied directly in the catalytic hydrothermal degradation of glycerol to lactic acid with its yield of 80.5%.

Lactic acid is believed as one of the most promising organic acids in the twenty-first century which is widely applied in food, drink, medicine, health and other chemical industry. Poly(lactic acid) (PLA) from the polymerization of lactic acid is a new biopolymer, which is non-poisonous, degradable, biocompatible, and widely used in producing biodegradable plastics, green package materials and medicinal restoration materials. By using the process developed, high yield of biodiesel is achieved, and by-product glycerol is further converted to lactic acid. Therefore, this process is a green and cost-effective for the sustainable development of biodiesel industry.

Related references:

1 Y. D. Long, F. Guo,Zhen Fang* et al., Production of biodiesel and lactic acid from rapeseed oil using sodium silicate as catalyst, Bioresource Technology, 102, 6884-6886 (2011).http://dx.doi.org/10.1016/j.biortech.2011.04.007

2 Y. D. Long, F. Guo,Zhen Fang* et al. A method for co-production of biodiesel and lactic acid. (Patent Number: CN201010537935, 5)