The purpose of this study was to produce microbial oil from Yarrowia lipolytica Po1g grown in defatted rice bran hydrolysate. After removing oil from rice bran by Soxhlet extraction, the bran is subjected to acid hydrolysis with various sulfuric acid concentrations (1–4% v/v), reaction times (1–8 h), and reaction temperatures (60–120°C). The optimal conditions for maximum total sugar production from the hydrolysate were found to be 3% sulfuric acid at 90°C for 6 h. Glucose was the predominant sugar (43.20 ± 0.28 g/L) followed by xylose (4.93 ± 0.03 g/L) and arabinose (2.09 ± 0.01 g/L). The hydrolysate was subsequently detoxified by neutralization to reduce the amount of inhibitors such as 5-hydroxymethylfurfural (HMF) and furfural to increase its potential as a medium for culturing Y. lipolytica Po1g. Dry cell mass and lipid content of Y. lipolytica Po1g grown in detoxified defatted rice bran hydrolysate (DRBH) under optimum conditions were 10.75 g/L and 48.02%, respectively.

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AbstractThis study was conducted to fabricate scaffold from polylactic acid (PLA) and hydroxyapatite (HA) extracted from waste bovine bone for enhancing both mechanical and biocompatible properties. After pretreatment in dilute NaOH solution, the bone was calcined at 900°C for 6 h, ball milled and converted to HA. Factors that affect the formation of HA were investigated. Experimental results showed that HA particles with crystal size < 100 nm and 99% crystallinity could be obtained at 90°C, pH 11 and 35 mM H3PO4 solution followed by 4 h calcination at 900°C. By using non-solvent induced phase separation method, PLA scaffolds with pore size and surface area of 22.6 μm and 25.7 m2/g, respectively, containing different hydroxyapatite were successfully prepared. Tensile strength of scaffolds increased due to effective support by HA grafted collagen. PLA scaffolds containing HA were more degradable than PLA scaffolds and PLA scaffolds containing HA grafted collagen. Cell culture results showed that cell density increased significantly on porous scaffolds than that on the dense scaffolds. Moreover, cell density also increased significantly on the scaffold containing HA grafted collagen than that on the scaffold with pure HA.

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