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Developing of a novel enantioselective biocatalyst acting on L-amino acids of biotechnological interest through a "semi-rational design" approach supported by computational analyses.
Full text linkThe synthesis of optically pure enantiomers is a challenge for traditional chemistry. Enzymes often perform better than inorganic catalysts because of their enantioselectivity, effectiveness and ecological sustainability. However, natural enzymes that evolved under the drive of natural selective pressure for their biological function, are not suitable for most industrial applications 1. For this reason, enzymes must be improved by protein engineering.
L-amino acid deaminase from Proteus myxofaciens (PmaLAAD) catalyzes the oxidative deamination of L-amino acids (AAs) to the corresponding -keto acids (KA). This biocatalyst can be used for the setup “green processes” to produce pure KA and D-AAs, which are used as raw materials for the synthesis of drugs and agrochemicals. In this project, several biocatalytic processes based on PmaLAAD have been optimized for the bioconversion, deracemization and stereoinversion of (un)natural L-AAs 2. Several natural or synthetic L-AAs have been used as substratet obtaining conversion yields close to 100%. The knowledge of the 3D structure of PmaLAAD 3 was exploited to produce several enzyme variants possessing animproved activity on L-1-naphthylalanine (L-1-Nal) through a semi-rational design approach supported by computational analysis. The most interesting variant (F318A/V412A/V438P-PmaLAAD) was able to convert D,L-1-Nal with a rate 7.5 fold higher than the wild type
Demographic risk indicators in pay-as-you-go pension funds
No full textThis paper deals with demographic risk in private pay-as-you-go pension systems. In particular, it analyzes the
financial sustainability of the fund in a stochastic framework. The authors present a model to investigate the dynamics
of these types of pension funds which operate according to the pay-as-you-go rule, focusing on the behavior
of the demographic variable “new entrants” and on its influence on the future evolution of the fund. The
global asset return and the new entrants variation rate are modelled by autoregressive processes. The goal is to
propose risk indicators that can be employed to monitor the solvency of the fund. A numerical application is
carried out using the data provided by the pension funds of Italian professional orders. The analysis highlights
how the variable “new entrants” influences the final value of the fund and the application shows that the proposed
controlling model appears effective at providing advance warning of the financial insolvency of the fund.This paper deals with demographic risk in private pay-as-you-go pension systems. In particular, it analyzes the
financial sustainability of the fund in a stochastic framework. The authors present a model to investigate the dynamics
of these types of pension funds which operate according to the pay-as-you-go rule, focusing on the behavior
of the demographic variable “new entrants” and on its influence on the future evolution of the fund. The
global asset return and the new entrants variation rate are modelled by autoregressive processes. The goal is to
propose risk indicators that can be employed to monitor the solvency of the fund. A numerical application is
carried out using the data provided by the pension funds of Italian professional orders. The analysis highlights
how the variable “new entrants” influences the final value of the fund and the application shows that the proposed
controlling model appears effective at providing advance warning of the financial insolvency of the fund
Solvency indicators for partially unfunded pension funds
No full textThis study addresses the issue of the management of a partially unfunded pension fund in a stochastic framework. In
particular it focuses on the sustainability of a pay-as-you-go pension fund with a funded component. The model proposed
is developed in a continuous time and the two stochastic variables are the return on the assets and the intensity of
new entrants. The former are driven by a Vasiceck process and the latter is modelled by a mean reverting process. The
goal is to monitor the solvency of the fund, namely its capability to pay future obligations. To check the financial stability
of the fund, risk indicators are proposed.
The methodology is applied to the pension fund of Italian Professional Orders, pension funds that follow a not pure
pay-as-you-go pension scheme, but have a funded component.
Finally, some examples illustrate how the management of the fund can activate the correctives to rebalance the fund
solvency
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