Bioconversion of phytosterols to androstanes by mycobacteria growing on sugar cane mud

Direct sterol conversion of sugar cane mud (residue) by Mycobacterium sp. was demonstrated to be possible technologically, thus avoiding sugar cane oil extraction and further processes of extraction and purification of phytosterols from this oil. Indeed, mycobacterial cells were able to convert phytosterols from sugar cane mud into 4-androstene-dione (AD) and 1,4 androsta-diene-3,17-dione (ADD). For the various concentrations assayed, concomitant higher yields for both androstanes were achieved at 20% (w/w) sugar cane mud in media. Furthermore, conversions were similar to those from other substrates, such as a mixture of phytosterols. The results suggest that the mycobacterial cell is able to easily access and bioconvert sugar cane mud phytosterols.     

Simultaneous saccharification and fermentation of steam-pretreated bagasse using Saccharomyces cerevisiae TMB3400 and Pichia stipitis CBS6054

Sugarcane bagasse--a residue from sugar and ethanol production from sugar cane--is a potential raw material for lignocellulosic ethanol production. This material is high in xylan content. A prerequisite for bioethanol production from bagasse is therefore that xylose is efficiently fermented to ethanol. In the current study, ethanolic fermentation of steam-pretreated sugarcane bagasse was assessed in a simultaneous saccharification and fermentation (SSF) set-up using either Saccharomyces cerevisiae TMB3400, a recombinant xylose utilizing yeast strain, or Pichia stipitis CBS6054, a naturally xylose utilizing yeast strain. Commercial cellulolytic enzymes were used and the content of water insoluble solids (WIS) was 5% or 7.5%. S. cerevisiae TMB3400 consumed all glucose and large fraction of the xylose in SSF. Almost complete xylose conversion could be achieved at 5% WIS and 32 degrees C. Fermentation did not occur with P. stipitis CBS6054 at pH 5.0. However, at pH 6.0, complete glucose conversion and high xylose conversion (>70%) was obtained. Microaeration was required for P. stipitis CBS6054. This was not necessary for S. cerevisiae TMB3400.     

完全混合生物工艺脱除二氧化硫气体

运用完全混合生物处理工艺, 以预酸化的废糖蜜作为碳源进行了微生物法去除SO₂ 气体的研究, 在简单粗放的实验条件下, 研究了脱硫脱硫弧菌对预酸化的废糖蜜中有机酸的利用情况和对较高浓度SO₂ 气体的去除效果, 并对产物H2S 在第二级生物反应器中的去除率进行了测定。实验结果表明, 脱硫脱硫弧菌能利用预酸化的废糖蜜中的丙酮酸和乳酸作为碳源, 乙酸作为主要转化产物, 当二氧化硫进口浓度在1 865?4 637 mg/m³ 之间时, 在1#生物反应器中, SO₂ 去除率在91%以上, 最终出口SO₂ 去除率为95.5%, 产生的H₂S 在2#反应器中几乎被脱氮硫杆菌全部转化,平均去除率为98%, 菌体浓度均十分稳定, 系统运行状况良好。     

甘蔗糖蜜酒精废液混菌发酵菌体蛋白的研究

本文报导利用甘蔗糖蜜酒精废液混菌发酵高质量菌体蛋白的研究,通过热带假丝酵母Ｃａｎｄｉｄａ ｔｒｏｐｉｃａｌｉｓ种合融合株Ｃｔ－３配伍其他菌株,混菌发酵时间缩短２￣４ｈ,生物量可达２０ｇ／Ｌ,粗蛋白质含量５０￣５３％,灰份≤１０％,水分为５￣８％,与Ｃｔ－３单菌发酵相比,蛋白质提高４￣６％。     

Flow injection analysis system for the supervision of industrial chromatographic downstream processing in biotechnology

Sugar beet molasses is a natural resource for various products used in daily life, ranging from sucrose to amino acids for pharmaceutical industry. The separation of molasses into these high value components is performed on a large scale by ion exchange/exclusion chromatography. A biosensor system was set up for the “in time” analysis of serine and sucrose during molasses desugarisation. -Serine was analysed with the multi-enzyme system -serine dehydratase/lactic dehydrogenase and photometric detection of the NADH consumed. Sucrose was determined with invertase/mutarotase/glucose oxidase and the oxygen consumed was monitored amperometrically. An analysis could be performed within 2–5 min by directly injecting samples from the chromatographic process into the flow injection analysis system. The determination range for the sucrose analysis was 0–2.5 gl⁻¹ and for the analysis of -serine 0–0.5 gl⁻¹. The standard deviation for the measurement of -serine was 1.7%.     

Decolorization of dye and molasses by continuous and semi-continuous jar-fermentor cultures ofGeotrichum candidum Dec 1

Two culture modes, continuous and semi-continuous, of the decolorization fungus,Geotrichum candidum Dec 1, were compared to obtain a high treatment efficiency of molasses decolorization and a large productivity of peroxidase (DyP) to simultaneously decolorize dyes and molasses. The continuous culture ofG. candidum Dec 1 using a 5-l jar-fermentor showed high DyP activity at a low dilution ratio of 0.005h⁻¹, and decolorization ratio of molasses of 80% was obtained concomitantly. Therefore, a semi-continuous culture was performed by repeated refill and draw. In this mode, approximately 1.5 liters of the culture broth was replaced per cycle when the decolorization ratio of molasses was near 80%. The molasses medium (1.0 liter per day) was treated and the peroxidase productivity in the drawn culture broth was 26.6 U/day, whereas the peroxidase productivity was 17.9 U/day in the continuous culture with a dilution rate of 0.005 h⁻¹. The semi-continuous treatment system was an efficient decolorization method for the strain,G. candidum Dec 1.     

Genome‐wide DNA markers to support genetic management for domestication and commercial production in a large rodent,the Ghanaian grasscutter (Thryonomys swinderianus)

Domestication and commercial production of the grasscutter, Thryonomys swinderianus, a large rodent, represents an important opportunity to secure sustainable animal protein for local communities in West Africa. To support production, DNA markers are required for population diversity assessment, pedigree analysis and marker‐assisted selection. This study reports the application of double‐digest RAD sequencing to simultaneously discover and genotype SNP markers in 24 wild and recently domesticated grasscutters. An initial panel of 1209 SNP loci was characterised from a total of more than 21 000 candidate loci containing single SNPs. This genome‐wide resource represents the first application of its type to commercial production of a large rodent for food and advances the use of agricultural genomics in Ghana.     

Cell wall invertases of sugar cane

A study of the cell wall invertases in the different organs of a sugar cane cultivar has been undertaken. The enzymes could not be separated from the cell wall. They are compared on the basis of optimum pH, K_m, the effect of various chemicals and the substrate specificities of the preparations. According to the results each organ appears to possess a set of cell wall invertases with predominance of a different activity in each case.     

Development of the foetal membranes in the cane rat (Thryonomys swinderianus): a re-interpretation

The morphogenesis of the foetal membranes of the African cane rat (Thryonomys swinderianus, Temminck) was studied and compared with that of the caviomorphs from South America. Like the guinea pig and chinchilla, implantation in the cane rat is interstitial, amniogenesis is by cavitation, there is very early and complete inversion of yolk sac endoderm, there is a well-developed subplacenta which persists throughout gestation, and the interhaemal membrane is haemomonochorial in nature. The phylogenetic significance of these findings are discussed in the light of long geographical and temporal separation between the continents.