以微生物催化劑轉化固體有機廢棄物為無毒增值產物(1/2)

"Responsible consumption and production" is one of the United Nations' Sustainable Development Goals (SDGs) in 2030. In Taiwan, Circular Economy is also a focus of the 5+2 Industries Initiatives. Fish viscera, bagasse, and okara are common organic solid wastes. They are often reused as animal feed and fertilizer with limited values. In order to solve the subsequent environmental derivation of agricultural waste and to achieve the value. In this study, high-value heat-resistant alkaline protease (Alcalase) and α- ketoisocaproate (KIC) were manufactured from organic solid wastes. In the study of Alcalase production, the plastid of producing green fluorescent protein and Alcalase production, respectively, were transformed into Bacillus megaterium YYBM1 by molecular cloning. The parameter of heterologous protein expression was optimized by YYBM1-gfp, which could express a green fluorescent protein, and applied to YYBM1-subC, which could express Alcalase. Under 1% xylose induction, the heterologous protein produced by xylose derived from bagasse was higher than a commercial one. After the optimal enzyme hydrolysis conditions were obtained, YYBM1-subC pellets were added to the fish viscera and okara solution at pH 9.0 and 60 ℃ for two hours. When cells lysed, the intracellular enzyme was released, which could hydrolyze the fish viscera and soybean residue. The cost of Alcalase produced by xylose using fish waste medium and bagasse was 19 times higher than the commercial version. In the study of KIC production, an extracellular protease that Bacillus subtilis produced was used to hydrolyze the protein of fish waste into amino acid, which could provide a nitrogen source for bacteria. The amount of leucine in the total amino acid of fish waste is about 10.1%, which was the precursor of KIC. Therefore, by knocking out a gene, bkdAB that can metabolize the KIC gene, and heterologous protein expression to increase KIC yield. In the metabolic process, Bacillus subtilis mutant ∆bkdAB+LAAD not only has a high amino acid utilization rate. After cultivation, organic solid waste can effectively reduce 8.2% (w/w), and CO2 production can be reduced by nearly half (43.3%) compared with wild type. Therefore, this plan not only successfully uses microorganisms to transform solid organic waste into non-toxic value-added products but also echoes the circular economy and low carbon emission proposed by the United Nations and Taiwan government.