Lipase Production by Limtongozyma siamensis , a Novel Lipase Producer and Lipid Accumulating Yeast

Sakpuntoon Varunya,Limtong Savitree,Srisuk Nantana 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.11

Lipase is a well-known and highly in-demand enzyme. During the last decade, several lipase optimization studies have been reported. However, production costs have always been a bottleneck for commercial-scale microbial enzyme production. This research aimed to optimize the conditions for lipase production by Limtongozyma siamensis DMKU-WBL1-3 via a One-Factor-At-a-Time (OFAT) approach combined with statistical methods while using a low-cost substrate. Results suggest that low-cost substrates can be substituted for all media components. An optimal medium was found, using response surface methodology (RSM) and central composite design (CCD), to consist of 0.50% (w/v) sweet whey, 0.40% (w/v) yeast extract (food grade), and 2.50% (v/v) palm oil with the medium pH adjusted to 4 under shaking flask cultivation. From an economic point of view, this work was successful in reducing production costs while increasing lipase productivity. The medium costs were reduced by 87.5% of the original cost while lipase activity was increased by nearly 6-fold. Moreover, lipase production was further studied in a 2-L stirred-tank fermentor. Its activity was 1,055.6 ± 0.0 U/ml when aeration and agitation rates were adjusted to 1 vvm and 170 rpm, respectively. Interestingly, under this optimal lipase production, the yeast showed accumulated lipids inside the cells. The primary fatty acid is a monounsaturated fatty acid (MUFA) that is typically linked to health benefits. This study hence reveals promising lipase production and lipid accumulation by L. siamensis DMKUWBL1-3 that are worthy of further study

Alumina-doped Alginate Gel as a Cell Carrier for Ethanol Production in a Packed-bed Bioreactor

Jirawan Mongkolkajit,Jiranan Pullsirisombat,Savitree Limtong,Muenduen Phisalaphong 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.3

Alumina-doped alginate gel (AEC) was developed as a new type of cell carrier to be used in ethanol fermentation. The presence of the alumina particles in alginate gel not only improved the porous structure of the carrier, but also provided many advantageous characteristics including good mechanical strength, high stability, and high immobilization yield. The attachment of alumina particles and yeast cells by electrostatic attraction was shown to promote cell growth and increase ethanol productivity. The AEC carrier was found to be more effective for the immobilization of Saccharomyces cerevisiae M30 than the conventional Ca-alginate bead. Ethanol productivities of 1.4 and 7.9 ~ 12.6 g/(L/h) were obtained using the AEC cultures in batch and continuous modes of operation, respectively, with an ethanol yield of 43.9 ~ 46.7% and an immobilized yield of 81.4 ~ 84.5%. Ethanol fermentation in a continuous packed-bed reactor using the AEC carrier was stable for > 30 days.

Fed-batch Fermentation of Indole-3-acetic Acid Production in Stirred Tank Fermenter by Red Yeast Rhodosporidium paludigenum

Pumin Nutaratat,Nantana Srisuk,Panarat Arunrattiyakorn,Savitree Limtong 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.3

Indole-3-acetic acid (IAA) is a significant secondary metabolite that is the most important auxin of plant hormones. Production of IAA is considered to be a key trait to support plant growth. The improvement of IAA production by a basidiomycetous red yeast Rhodosporidium paludigenum DMKU-RP301 was investigated. Batch and fed-batch fermentation of R. paludigenum DMKU-RP301 were conducted in a 2 L stirred tank fermenter. Using batch fermentation, it was found that when cultivated at an agitation speed of 200 rpm and a 3 L/min aeration rate, this yeast produced IAA at its maximum level of 1,627.1 mg/L (9.7 mg/L/h). In fed-batch fermentation, a higher level of maximum IAA production than that found in batch fermentation was observed, i.e. 2,743.9 mg/L (25.4 mg/L/h). It is therefore suggested that fed-batch fermentation improves the efficiency of IAA production in terms of product concentration and IAA productivity. Moreover, yeast carotenoid production was also investigated using R. paludigenum DMKU-RP301, and found a maximum carotenoid production of 3.05 mg/L.

Biosynthetic Pathway of Indole-3-Acetic Acid in Basidiomycetous Yeast Rhodosporidiobolus fluvialis

( Sakaoduoen Bunsangiam ),( Varunya Sakpuntoon ),( Nantana Srisuk ),( Takao Ohashi ),( Kazuhito Fujiyama ),( Savitree Limtong ) 한국균학회 2019 Mycobiology Vol.47 No.3

IAA biosynthetic pathways in a basidiomycetous yeast, Rhodosporidiobolus fluvialis DMKUCP293, were investigated. The yeast strain showed tryptophan (Trp)-dependent IAA biosynthesis when grown in tryptophan supplemented mineral salt medium. Gas chromatography-mass spectrometry was used to further identify the pathway intermediates of Trpdependent IAA biosynthesis. The results indicated that the main intermediates produced by R. fluvialis DMKU-CP293 were tryptamine (TAM), indole-3-acetic acid (IAA), and tryptophol (TOL), whereas indole-3-pyruvic acid (IPA) was not found. However, supplementation of IPA to the culture medium resulted in IAA peak detection by high-performance liquid chromatography analysis of the culture supernatant. Key enzymes of three IAA biosynthetic routes, i.e., IPA, IAM and TAM were investigated to clarify the IAA biosynthetic pathways of R. fluvialis DMKU-CP293. Results indicated that the activities of tryptophan aminotransferase, tryptophan 2-monooxygenase, and tryptophan decarboxylase were observed in cell crude extract. Overall results suggested that IAA biosynthetic in this yeast strain mainly occurred via the IPA route. Nevertheless, IAM and TAM pathway might be involved in R. fluvialis DMKU-CP293.

Cellulose degrading basidiomycetes yeast isolated from the gut of grasshopper in Korea

김주영,장준휘,박지현,정희영,박종석,조성진,이훈복,성기호,김명겸,Kim, Ju-Young,Jang, Jun Hwee,Park, Ji-Hyun,Jung, Hee-Young,Park, Jong-Seok,Cho, Sung-Jin,Lee, Hoon Bok,Limtong, Savitree,Subramani, Gayathri,Sung, Gi-Ho,Kim, Myung The Microbiological Society of Korea 2018 미생물학회지 Vol.54 No.4

메뚜기는 광합성으로 고정된 탄소의 소화에서 중요한 역할을 한다. 장내 미생물 군의 도움으로, 메뚜기는 셀룰로오스 및 헤미셀룰로오스와 같은 잎의 성분을 분해할 수 있다. 본 연구는 한국의 기도에서 수집한 메뚜기 껍질에서 추출한 셀룰로오스 분해 효모 균주를 조사하기 위해 이루어졌다. 효모 균주 중 ON2와 ON17 (두 균주)과 ON6 (한 균주)는 CMC-플레이트 분석에서 셀룰로오스 활성을 보였다. Large subunit rDNA의 D1/D2영역의 서열과 internal transcribed spacer (ITS) 영역의 분석 결과, ON2와 ON17 균주가 Papiliotrema aspenensis CBS $13867^T$와 가장 밀접하게 관련되어 있었고(D1/D2 영역의 서열 유사성은 100% ITS에서 99.4%의 서열 유사성) ON6 균주는 Saitozyma flava와 관련된(D1/D2영역에서 100%, ITS에서 99.0%) 밀접하게 관련이 있었다. 이 세 가지 효모 균주는 모두 셀룰로오스를 분해할 수 있으므로 공생하는 효모들은 탄수화물 분해를 위한 효소를 자체적으로 생산하고 당 단당체를 휘발성 지방산으로 전환시킬 수 있다. Tremellomycetes에 속하는 공생 효모 균주인 ON2, ON17 (Papilioterma 속)과 ON6 (Saitozyma속)은 한국에는 보고되지 않은 균주이다. Grasshoppers play vital role in the digestion of photosynthetically fixed carbons. With the aid of intestinal microflora, the grasshopper can degrade leaves constituents such as cellulose and hemicellulose. The purpose of this study was to examine cellulolytic yeast isolates from the gut of grasshoppers collected in Gyeonggi Province, South Korea. Among the yeast isolates, ON2, ON17 (two strains), and ON6 (one strain) showed positive cellulolytic activity in the CMC-plate assay. The sequence analyses of D1/D2 domains of the large subunit rDNA gene and the internal transcribed spacer (ITS) regions revealed that the strains ON2 and ON17 were most closely related to Papiliotrema aspenensis CBS $13867^T$ (100%, sequence similarity in D1/D2 domains; 99.4% sequence similarity in ITS) and strain ON6 related to Saitozyma flava (100% in D1/D2 domains; 99.0% in ITS). All these three yeast strains are capable of degrading cellulose; therefore, the members of endosymbiotic yeasts may produce their own enzymes for carbohydrate degradation and convert mobilized sugar monomers to volatile fatty acids. Thus, the endosymbiotic yeast strains ON2, ON17 (represents the genus Papilioterma) and ON6 (Saitozyma) belonging to the family Tremellomycetes, are unreported strains in Korea.