Skin colour is an important criterion in determining the aesthetic appeal of ornamental fishes,and thus their market worth.Hence the pigment enhancement in ornamental fishes has been the subject of extensive research by using various synthetic as well as natural pigment sources.Dietary composition is one of the most important elements that influence the development of pigmentation in fish.This study is an attempt to assess the possibility of using carotenogenic marine yeast as pigment enhancer in fish diet for Koi carp,Cyprinus carpio.The 60 days feeding experiment was done by using feed incorporated with mangrove associated marine yeast Rhodotorula paludigena VA242.Greater pigmentation in the scales of fishes fed with experimental feed was observed than that fed with the control diet(normal pellet feed).Furthermore the improved growth rate and general wellbeing in fishes fed with experimental feed provides scope for further studies in this field with respect to the growth and survival of fishes.
Terpenoids have tremendous biological activities and are widely employed in food,healthcare and pharmaceutical industries.Using synthetic biology to product terpenoids from microbial cell factories presents a promising alternative route compared to conventional methods such as chemical synthesis or phytoextraction.The red yeast Rhodotorula mucilaginosa has been widely studied due to its natural production capacity of carotenoid and lipids,indicating a strong endogenous isoprene pathway with readily available metabolic intermediates.This study constructed several engineered strains of R.mucilaginosa with the aim of producing different terpenoids.Monoterpeneα-terpineol was produced by expressing theα-terpineol synthase from Vitis vinifera.The titer ofα-terpineol was further enhanced to 0.39 mg/L by overexpressing the endogenous rate-limiting gene of the MVA pathway.Overexpression ofα-farnesene synthase from Malus domestica,in combination with MVA pathway rate-limiting gene resulted in significant increase inα-farnesene production,reaching a titer of 822 mg/L.The carotenoid degradation productβ-ionone was produced at a titer of 0.87 mg/L by expressing theβ-ionone synthase from Petunia hybrida.This study demonstrates the potential of R.mucilaginosa as a platform host for the direct biosynthesis of various terpenoids and provides insights for further development of such platforms.
Qiongqiong ChenLiting LyuHaizhao XueAabid Manzoor ShahZongbao Kent Zhao
Microbial lipid fermentation encompasses intricate complex cell growth processes and heavily relies on expert experience for optimal production.Digital modeling of the fermentation process assists researchers in making intelligent decisions,employing logical reasoning and strategic planning to optimize lipid fermentation.It this study,the effects of medium components and concen-trations on lipid fermentation were investigated,first.And then,leveraging the collated data,a variety of machine learning algorithms were used to model and optimize the lipid fermentation process.The models,based on artificial neural networks and support vector machines,achieved R?values all higher than 0.93,ensuring accurate predictions of the fermentation process.Multiple linear regression was used to evaluate the respective target parameter,which were affected by the medium components of lipid fermentation.Lastly,single and multi-objective optimiza-tion were conducted for lipid fermentation using the genetic algorithm.Experimental results demonstrated the maximum biomass of 50.3 g·L^(-1) and maximum lipid concentration of 14.1 g:L^(-1) with the error between the experimental and predicted values less than 5%.The results of the multi-objective optimization reveal the synergistic and competitive relationship between biomass,lipid concentration,and conversion rate,which lay a basis for in-depth optimization and amplification.
